OBSERVATIONS ON THE CRUSTACEAN FAUNA OF THE 
REGION ABOUT MAM.MOTH CAVE, KENTUCKY. 
By William Perky Hay, 
Howard Inirerxiti/, Washington City. 
During- the month of August, 1901, the writer spent a weelc at the 
Mammoth Cave of Kentucky and, through the courtesy of Mr. H. C. 
Ganter, the manager of the estate, was able to make fairly complete 
collections of the invertebrates, both within the cave and in various 
neighboring springs and streams. As the object of the visit was to 
obtain extensive series of the crustaceans of the region, and to record 
observations on their habits, very little attention was paid to other 
groups, and aside from the crustaceans the collections were very mea- 
ger. A few specimens of an earthworm resembling L>n/thricits, a (juan- 
tity of fresh-water sponge taken from the rocks well within the exit of 
Echo River, and one or two specimens of Cottus sp. {rlcjKirdKoiu! f) 
taken in Roaring River are the only ones worthy of note. 
As is well known, the Mammoth Cave of Kentucky has been the sub- 
ject of many articles long and short, or volumes, which have appeared 
from time to time. Its fauna has been studied more carefully and 
by more naturalists than that of any other American cavern, as numer- 
ous lists and papers will testify. 
•The localities given in the present paper are often those within the 
cave, but the name by which the particular spot is known is usually 
given for the sake of accuracy. Richardson's Spring is a small pool 
of clear water supplied b}^ a very small trickling stream and is about 
1 mile from the entrance. Roaring River, a passage which is never 
visited except b}- the collector, is reached by a low and very nmddy 
and difficult passage which turns off from the main route a short dis- 
tance l)e3"ond Echo River. The mouth of the passage is said to be 2 
miles from the entrance of the cave. At times of high water the 
entire passage, as well as contiguous portions of the main cave, are 
flooded, but usually the water is confined to a series of small pools 
among the rocks and mud of the floor of the passage and the stream 
at the end. Roaring River itself is a stream some 15 or 20 feet wide. 
Proceedings U. S. National Museum, Vol. XXV-No. 1285. 
223 
224 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxv.. 
and an av^erage depth of 1 foot. It flow.s with a .stead}' current and is 
known to be a part of Echo River. 
All the specimens upon which this paper is based have been depos- 
ited in the United States National Museum. 
Suborder AMPHIPODA. 
Family GAMMA RID.E. 
GAMMARUS PROPINQUUS, new species. 
fyjj^^—]^o. 25545, U.S.N.M. Collected by W. P. Hay, August 
28, 1901, from a spring- about 2 miles north of Manunoth Cave, Ken- 
tucky, 
DeHi-rlptJtm. — Similar to Gaiiuiiai'ux fa.sciati(-'< Say. but with the 
following- characters : 
First pair of antennae less than half as long as the body, the Hagellum 
with about twenty-live segments, the accessory branch nmch shorter 
than either segment of the peduncle and composed of but two or three 
segments. 
Second antennte from half to three-fourths as long as the first; the 
second and third basal segments of about equal length; the Hagellum 
slightly longer than either segment and composed of twelve articles. 
First pair of gnathopoda with the inferior margin of the carpus and 
hand rather densely fringed with hairs, the longest of which are equal 
to the width of the carpus; hand with the palmar surface very oblique, 
hardly distinguished from the inferior surface, armed with a few long 
bristles and short teeth; dactyl much curved. 
Second pair of gnathopoda larger, stronger, the palmar surface less 
oblique, being at an angle of about 50 degrees with the inferior surface; 
carpus and hand fringed with hairs as in the preceding appendage; 
dactyl stronger and straight. 
Basal segments of the last three pairs of pereiopoda lamellar as usual, 
but with the posterior margin entire and almost unarmed; the succeed- 
ing segments more or less armed with hairs and short spines, but nowhere 
excessivel}'. 
Eye elongate, reniform. 
Fifth and sixth abdominal segments with median and lateral groups 
of spines on their posterior margins. Seventh segment with a few 
scattered spines, apparently not arranged in groups, along the posterior 
margin. 
Telson cleft to its base; each division with the distal extremity armed 
with a tran verse row of slender spines; outer margin with two rather 
slender spines. 
Rentarl'ti. — This species, which appears to be distinct from any 
hitherto described, was found in small numbers in several localities in 
the region about Mammoth Cave. The best specimens were obtained 
NO. 12«5. FA UNA OF MAMMOTH CA VE—HA Y. 225 
from the type locality and a few good ones were taken at the outlet of 
Echo Kiver. In color they were a purplish gray. They were hiding 
under flat rocks in the cold spring water. 
CRANGONYX VITREUS Cope. 
This species was observed in considerable numbers in Mannnoth 
Cave, both in its type locality, Richardson's Spring, and in the Roar- 
ing River district in small pools. When undisturbed it was most often 
seen resting quietly or walking slowl}^ through the nmd on the bot- 
tom with the bod}^ vertical and half buried in the soft ooze of the sur- 
face. As a result of these movements there were innumerable trails 
running in all directions, but never of a great length, as if the animal, 
tiring of walking through the mud, had decided to swim to some more 
renuuierative feeding ground. When once disturbed they swam rap- 
idly about, either on their sides or with the back uppermost, or sought 
safety l)y lying quietly behind some projecting pebble or mass of 
earth. It was observed that when concealing themselves the}^ usually 
lay on one side. Owing to their exceedingly smooth covering and 
small size they were ver}^ difficult to catch. 
Suborder ISOPODA. 
Family ASELLID^E. 
MANCASELLUS MACRURUS Harger. 
This species was observed in two or three localities. A few speci- 
mens were taken in a spring some 2 miles northeast of the hotel. They 
seemed to be all very small and immature, but on careful examination 
several of them could be seen carrying eggs. 
At the so-called mouths of Echo River, a series of three large 
springs at the foot of the hill in which the entrance to Mammoth 
Cave is found, If. iiiacrurm was collected in abundance. They were 
of rather small size but decidedly larger than the specimens taken 
from the spring mentioned above. 
They were usually found clinging to the under side of Hat rocks, 
which lay in shallow water, and until a large number was disturbed 
by turning over rocks I was not able to observe any of them crawling 
al)out. They were living at this place in company with about equal 
numbers of Aselhis styglas (Packard). The association seemed indis- 
criminate, for I could not see that either species was partial to any 
particular location or condition in the spring. 
C^CIDOTEA STYGIA Packard. 
This well-known species was taken in considerable numbers from a 
small stream in one of the upper levels of Mammoth Cave and was 
found in smaller numbers in small pools in other parts of the cavern. 
Proc. N. M. vol. XXV— 02 15 
226 PROCEEDINGS OF THE NATIONAL MUSEUM. 
It was also found in abundance at the mouth of Echo River, where 
it was livino- in conipan}' with 3L macrurus Harg-er. They were 
usually found clinoino- to the stone walls of the pool in which they 
were living- or could ])e seen slowly walking- over the bottom. When 
disturbed their -movements were considei-u])ly (luickened, but they 
were unable to move with any great rapidity. If when disturbed 
they were clinging to the sides of their pool their first effort to 
escape was by letting go and falling to the bottom; in case the pool 
was deep this method was quite effectual. When removed from the 
water they seemed almost absolutely helpless, the weak legs being 
quite inadequate to the task of dragging along the heavy body. 
Suborder MACRURA. 
Family ATYID.E. 
PAL/EMONIAS GANTERI Hay. 
Tyjye.—^o. 27000, U.S.N.M. 
A most unexpected find in the Roaring River passage at Mammoth 
Cave was a small eyeless shrimp, which proves to be a representative 
of a family hitherto unrecorded from the North American continent. 
The discovery was made one morning when I had gone alone into 
this passage with the intention of collecting as perfect a series as pos- 
sible of the blind crayfish. A number of large C. j^ellucidus had been 
secured, and I was endeavoring to find others of smaller size. To this 
end the bottoms and the water of the clear pools were being examined 
most carefully. While thus engaged, an ol)ject which seemed to be 
a very small eyeless fish, appeared swimming slowly along near the 
surface. From the way it moved in attempting to escape capture it 
became evident that it could not be a fish, and a determined effort was 
made to secure it. After a most exasperating chase, during which my 
specimen seemed more than once to have eluded me, it was captured, 
and I saw immediately that another animal had been added to the 
fauna of the cave. 1 then set about finding others, and, knowing 
what to look for, they were found quite easily. When first seen they 
were usually resting quietly or were slowly walking on the bottom of 
the pool, and were as insensible to the glare of my lantern as were the 
crayfish. They were so transparent that several times they were 
detected only by their shadows, and even when moving near the sur- 
face they were almost invisible. When disturbed they at once left 
the bottom, and by the rapid strokes of their subal)dominal append- 
ages came to the surface, where they remained for some time before 
sinking again to the bottom. All their movements were unmistakably 
shrimp-like and very different from those of any of the other crusta- 
ceans in the cave. They were very easily captured, either in the net 
NO. 1285. FA UNA OF MAMMOTH CA VE—HA Y. 227 
or Iw gentl}' slipping' iny hand beneath them as they swam slowly on 
the surface; in fact, the latter method Avas' used in nearly every case. 
Twelve specimens were put with a live e3^eless fish into a 8-ounce 
bottle, tightly corked, and without a change of water carried al)out in 
the cave for over four hours; on reaching the hotel most of them 
were still alive, and the few that were dead seemed to have been killed 
by the slime from the fish. Five of them lived for over two da3's in 
a tumbler of water on the table in ni}^ room, Avhere the temperature 
stood at times as high as 85 degrees. 
On reaching Washington a specimen was at once stained, dissected, 
and mounted, and I found that my shrimp was not onl}^ a new species 
but must stand as a representative of a new genus, to which the name 
Palxmonias was given, ^ with the specific name of ganteri in honor of 
the manager of the cave, Mr. H. C. Ganter, who aft'orded me the 
facilities for making- my collection. 
As the description mentioned was quite brief and unaccompanied by 
figures and regarded as only a preliminary notice, it seems advisable to 
introduce here a more detailed account of the characters of this some- 
what remarkable species. 
The carapace is veiy thin, delicate, and transparent, in form cylin- 
drical or slightly compressed; the greatest depth is near the posterior 
end; the anterior border, below the eye, is produced into two spini- 
form points, the upper of .which is the larger; the rostrum is slender 
and slighth" wider near the middle than at the base, the lower margin 
bears from one to three minute teeth, while on the upper margin there 
are about thirteen, of which the first two or three are at the veiy base, 
almost on the carapace, and are separated bj quite an interval from a 
group of eight or nine near the middle of the rostrum, which in turn 
are separated by a second small interval from the group near the distal 
extremit3\ 
TheaV)domen is compressed, rounded above, and exceeds the cephalo- 
thorax in length. The sixth segment is as long as the fourth and fifth 
coml)ined. The swimmeretts of the first segments are large and thickly 
fringed with setffi. 
U'roc. Biol. Soc. Washington, XIV, pp. 179-180, Sept. 25, 1901. 
PAL^^MONIAS, new genus. 
Similar to PaUemoneten in fonn and in the absence of a mandibular palpus. Ciills 
four and a rudiment on each side. Rostrum long, slender, and serrate above and 
below. Antero-lateral margin of carapace with two spines. First two pairs of 
ambulatory appendages subequal in size and similar in form, chelate and with large 
bunches of pectinate bristles on tlie tips of the fingers.' The articulation of the hand 
with the carpal segment is at a point on the lower surface of the hand some dis- 
tance from the proximal end, and the prominent knob-like extremity fits when the 
limt) is fully extended, into a broad sinus formed by the margin of a plate-like 
expansion of the carpus. 
228 
PROCEEDTNGS OF THE NATIONAL MUSEUM. 
The telson is elongate, slightly angulate and bispinose on the outer 
margin. The extremit}^ is arcuate and bears nine or ten slender spines. 
The outer blades of the tail fin are narrow and densely fringed with 
line hairs; the external one is indistinctly divided near the distal end 
by a sinuous transverse line, at the outer end of which there is a small 
spine and at the inner a projecting angle. 
The eyestalks ai'(^ rudimentary, but seem to be considerably more 
prominent than in such an analogous a form as Camharus 2>elhicidus. 
They arc ([uite short when compared with the rostrum, but are not 
hidden bv it. The distal extremity is without a trace of pigment or 
of facets and is bluntlv conical. 
a Right lateral view of tyiie siiecii 
h Left lateral view nf caiaiiace. 
c Mandible. 
d Basal segments of first antenna, 
e Basal segments of second antcni 
im HAY. 
/ Third maxilliped. 
;/ Second chelate thoracic appendage. 
/( Fifth thoracic appendage. 
( Appendage of sixth abdominal appei 
k Telson. 
The antennules are bitlagellate, the iiagellre ])eing of nearly cijual 
length and about as long as the antennte. The basal segment of the 
antennule is expanded somewhat so as to present toward the median 
line a nearly horizontal blade, which at about its middle is extended 
into a large, strong spine directed in the same line as the remainder of 
the appendage. 
The antennie are longer than the body, exceeding it by about half 
its length; they are verv slender; the scale is nearly as long as the ros- 
trum, its outer margin concave and terminating in a small spine some 
distance from the rounded extremity; the second basal segment )>ears 
on its outer distal angle a minute slender spine. 
The third maxillipeds are pediform and in all but size quite similar 
to the third, fourtli, and fifth walking legs. All these appendages of 
the thorax bear a hliform exopidite, which is usually at least as long 
as the combined lengths of the four basal segments of the appendages. 
The first and second pairs of pereiopods are so nearly equal in size 
that it is with great doubt that I venture the statement that the second 
FA rXA OF MAMMOTH CJA VE—HA Y. 229 
pair is the larger. They are probably slig-htly longer but more slen- 
der. The proximal half of the limb presents no unusual charaeters, 
])ut the distal half has the characters peculiar to the Atyida\ The 
proximal end of the carpus is slender and subcylindrical, but toward 
the distal end on the superior surface there appears a thin plate or 
ridge which gradually increases in height to a point just short of the 
distill end of the segment. Here it is abruptly excavated so as to pre- 
sent a broad sinus for the reception of the knob-like extremity of the 
hand. Below this sinus the carpus extends forward a short distance 
so as to articulate with the ventral surface of the hand and not its 
proximal end. The hand is subcylindrical, the postarticular portion 
is rounded, and, as stated above, is intended to fit closely into the sinus 
in the carpal expansion. The fingers are so curved as to meet only at 
their tips. They are apparently quite cylindrij,al and unarmed except 
at their tips, where they bear each a dense pencil of rather long, 
stiff, pluiuose or pectinate hairs. The hands and carpal segments are 
usually directed downward and l)ackward so as to In-ing the ventral 
finger to the lower side, and the degree of motion between the hand 
and the carpus seems to be very great. 
The dactyls of the last three pairs of pereiopods are minutely ser- 
rate, as are the distal extremities of the antepenultimate segment. 
The gills seem to be only four in number, on each side attached to 
the first four pereiopods, but there may be a rudiment on the fifth. 
Twelve specimens w-ere secured, varying in length from 14 to 28 
mm. from the tips of the rostrum to the end of the telson. In life 
they were colorless, but in alcohol they are milk white. 
When I first described this genus and species 1 was of the opinion 
that its affinities were with the Pala?monid{e and the genus PaJsenionetes, 
and the name Palse/monias was given to call attention to the fact. I 
had noticed the striking resemblance of the hand and carpal segment 
of the first two pairs of pereiopods to the similar parts of certain of 
the Atyidw, but did not consider this a character of sufficient weight to 
overbalance the striking resemblance to certain of the Pala3nionid{e in 
every other character. I have recently received a letter from Dr. 
A. E. Ortman, of Princeton Univei-sity, calling my attention to other 
characters, and, furthermore, I have been able to secure the descrip- 
tion of Troglocarlsschinklt! Dormitzer,^ and have thereby been forced 
to reverse my opinion. 
Paimtionim should certainly be placed in the family Atyidje, and is 
a very close relative of the genus Xlphocarh, from which it seems 
to differ by only one character, namely, the pronounced excavation 
of the carpal segments. I would not be willing to accept as a good 
generic character that of rudimentary eyes, as has l)een don(> in this 
family for the genus Troglocaris. 
1 Lotos, 3d year, 1853, p. 85, pi. iii, fig. 1-5. 
230 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxv. 
The figure of Olophonis americanus Saussure/ however, shows a 
rather deep excavation of the carpal seg-ments, and if Dr. Ortman is 
correct" in regarding this the same as Xlphocarls elongata., the dif- 
ferences l)etween Palxiuonlaa and Xi^lMcarls are very slight indeed. 
This species is of especial interest, since it has been shown by Dr. 
Ortman that the Atyidre are extremely archaic fresh-water crustaceans, 
and that of them the genus Xiphocaris is the most primitive. In 
former times the distribution of Xlj^hoearlft was probably far more 
extensive than it is at the present. To-dav but three surviving spe- 
cies are known to science, ''one from the fresh waters of the West 
Indies, another from streams and pools in Indo-Malaysia, and a third 
from the streams of New Zealand. " ^ The isolated species, Palxmonias 
ganteri and Trogolocaris f<chm!df!^ which, as has been pointed out, may 
prove to lie congeneric with Xip/ioearis, are species which have been 
left behind in the limestone caverns when the main bod}" of their rela- 
tives was swept to the south. 
It offers also another proof of the fact that we may look to the 
limestone caverns of the world for man}' of the most valuable clues 
to the relationships of our present surface fauna. There are doubt- 
less man}" cases in which the extension of habitat to the sul)terranean 
retreats has been quite recent; l)ut, in the main, cave-inhabiting animals 
are of archaic types and date from a time when conditions were more 
uniform, and consequently faunal differentiations were less marked 
than at the present day. In support of this sttitement it will be suf- 
ficient to mention the occurrence in Carniola of a subterranean species 
of crayfish very similar to those occurring to-day in North America, 
and quite different from those of Europe, and the more recent dis- 
covery in Texas of Ti/p/ih/nolge, a genus of blind, cave-inhabiting 
salamanders, which, so far as it is known, finds its nearest relatives in 
Proteu-^ of Carniola. 
Family ASTACIDyE. 
CAMBARUS PELLUCIDUS ( Tellkampf) . 
The "blind crayfish of Maumioth (^ave," which is now known to 
inhabit the subterranean water courses of a considerable portion of 
Kentucky and Indiana, was collected and observed frequently wherever 
conditions were favorable. The shallow margins of the "River Styx " 
and the small pools in the passage to Koaring River afforded me abun- 
dant opportunities to study this interesting species. It was no uncom- 
mon thing to have several under observation at one time. 
When first oliserved they were usually on the bottom, resting 
quietly with their legs and antennae fully extended. Unless they were 
^Mem. Soc. Phys. Hist. Nat. Geneve, XIV, Pt. 2, 1858, p. 472, pi. iv, iig. 31. 
^Proc. Acad. Nat. Sci. Phila., 1894, p. 400. 
■^Idem, p. 400. 
FA UNA OF MA MMO TH CA VE—HA Y. 231 
disturbed they would remain in this position for several minutes, and 
then with no apparent reason start off at a rapid gait, move to another 
spot, and take up the same position. While thus resting, the only 
movement ol)serva])le was a slight waving to and fro of the antenna. 
Sometimes an individual was seen on a submerged rock mass resting 
in the same way; such individuals appeared to have no difficulty in 
running rapidly over the rough surfaces. When alarmed in any way, 
the crayfish would begin to show signs of uneasiness by moving 
slightly about in various directions, and then dart away, propelled l)y 
the vigorous strokes of its tail fin. There seemed to be no al)ility on, 
the part of the animal to select a safe haven of refuge from a distance, 
for the fiight for safety was apt to end anywhere; the course was 
usually laid for deeper water, but if a rock or the wall of the pool was 
encountered the crayfish would quickly conceal itself in a crevice and 
retreat l)eyond reach of danger. Several individuals, when repeatedly 
chased across a small pool, became either too exhausted or too enraged 
to retreat and showed a readiness to fight by rising high on the front 
walking legs and waving their chelre about in the direction of the dan- 
ger. Their movements were very quick, probably more rapid than 
those of outside species, and it was difficult to touch their antennie 
and escape a nip from their chelre. 
Several specimens were obtained from places where the pools were 
nearly or quite dried up, and it was observed that in such places the 
crayfish had dug for itself a hole or had crawled under a stone and 
was making preparations to remain. They were already in a semi- 
dormant condition and in a few days would doubtless have died. The 
tracks of a cave rat, several excavations made by him, and the remains 
of a crayfish showed that even in the fastnesses of their subterranean 
home the crayfishes have enemies to which they sometimes fall victims. 
It has frequently been stated that disturbing the surface of the 
water is sufficient to frighten the crayfish. I did not find this to be the 
case unless the disturl)ance was great enough to affect not only the 
surface but the depths of the pool as well. Indeed I have often passed 
my hand completely around an individual, all ready and alert, and have 
brought my fingers within half an inch of its body without causing it 
to show further alarm. The instant it was actually touched either on 
its long, waving antenna^ or on any portion of its body it would dart 
awav. • I • 
From all the evidence which could be gathered it seems that m this 
creature the senses of sight and hearing have entirely disappeared. 
At the time of these investigations the interesting article ])y Prentiss/ 
on the otocysts of the crustacea was unknown to me and I was not led 
to repeat his experiments on the blind crayfish. So far as I am able 
to determine without careful microscopic examination the otocyst^f 
iC. W. Prentiss. The Octocyst of Decapod Crustacea; Its Structure, Development, 
and Functions. Bull. Mus. Conip. Zo.",]., XXXVI, No. 7. July, IWl. 
232 PROCEEDINGS OF THE NATIONAL MUSEUM. 
O. peUacldus is perf ectl}^ normal, but it can not 1)0 claimed that it is a 
functional organ of hearing-. The powers of equilibration in C. fellu- 
cidus are in no way inferior to those of the terranean species with 
well-developed eyes. It seems to me that the removal of the otocysts 
in such a blind species and the careful study of the animal's powers 
thereafter would give a basis for very definite conclusions as to their 
functions. 
In a series of twent}' specimens collected in the Roaring River 
passage ten were females, five were males of Form I, and five were 
males of Form 11. One of the males of Form I is quite soft, and I 
therefo]-e infer that ecydysis occurs in this species at about the same 
season as in surface-inhabiting species and that copulation takes place 
early in the fall. Eggs are said to be laid during the Avinter, l)ut the 
guides were rather indefinite as to the exact time. 
The smallest specimen collected, a female, is 21 nun. in length; it, as 
well as the next larger one (26 mm.), differs from the adults in having 
but one lateral thoracic spine. In a specimen 41 mm. in length all the 
spines above and in front of the lateral spine are developed. In a 
specimen 36 mm. long, from Echo River, one accessory spine is present 
just above the lateral spines, and a few minute granules on the sides of 
the head, in front of the cervical groove, indicate the patch of spines 
which is to l)e found in the adult. 
CAMBARUS BARTONI TENEBROSUS, new subspecies. 
7)/7>r.— No. 2231<;. r.S.N.M. Mammoth Cave, Kentuckv. R. E. 
Call. 
Dldrihiifion. — Known only from the type locality. 
Description. — Compared with the typical C. harton! from the 
neighborhood of Philadelphia, the carapace is less depressed and with 
more parallel sides, the areola is longer, the cephalic portion of the 
carapace is more robust, and the sides of the rostrum are more con- 
vergent. The antennas are slender and in length exceed the ])od3'. 
The eyes are reduced in size and the spine armature is much more 
strongh' developed. There is alwaj^s a small but acute spine on the 
side of the carapace just behind the cervical groove; the two spines 
on the upper surface of the distal end of the meros are usually well 
developed, and the median internal spine of the carpus is large and 
strong. In addition to these there usually are, in small individuals, 
well-developed spines at the anterior end of the pbstor])ital ridge and 
an acute branchiostegian spine. Throughout the entire series exam- 
ined there is great uniformity in these characters and thev contrast 
nicel}^ with another small series collected from small surface streams 
in the neighborhood of the cave. In these the antennas are shorter 
than the bod}'; the lateral spine of the carapace, even in small indi- 
viduals, is reduced to a ver}' weak and slender point; the spines on 
FA UNA OF MAMMOTH CA VE—HA Y. 233 
the upper distal portion of the raeros are obsolete, and the eyes are 
normally developed. 
The individuals from the cave range in length from 1U8 mm. to 35 
mm., while those from the surface range from 60 nun. to 10 mm. 
Bemarl's. — ^This form of C. hartoni^ which appears to ])e well 
marked, was found in considerable abundance in Echo River and the 
River Styx. Ten specimens were collected; one male. Form II, and 
nine females, two of which carried eggs. In addition to these I have 
examined a number of specimens from the same localities collected l)y 
Dr. R. E. Call and others. 
The fact of the existence of cra3"tish with eyes in Mammoth Cave 
in company with the eyeless C. jf>'(3/ZwY'/V///.s' has frequently been men- 
tioned by writers on the cave and its fauna but the eyed species has 
always l)een regarded as a transient or accidental form. It has even 
been supposed ' that the eyed and eyeless species interbreed so that 
"the blind form is continually reinforced by new blood from outside 
the cave."" Dr. Walter Faxon, in speaking of this theory," gives a 
number of reasons for discarding it, but later in a paragraph on C 
l^enueidxm testi Hay, which in its appearance is much more like C. hnr- 
ton'i than is C. i^elluddm, he seems to think that after all such a thing 
might be possible.^ 
During the course of some carcinological work the writer had occa- 
sion to review the variations of C. haHoni and spent over a month in 
the examination of several hundred specimens and considerable addi- 
tional data. The trip to Manmioth Cave was made largely for the pur- 
pose of stud3dng the relationship of the cave-inhabiting individuals to 
individuals living on the surface. 
As is Avell known Cambaras harton! Fabricius is a species with a 
very extensive range and therefore is subject to much variation. Its 
habits throughout the range are, so far as I know, practicalh* uniform 
unless conditions are such as to preclude the possibility of following 
the customary mode of living. It is a frequenter of cool streams 
where it lives under the flat rocks or in holes which it excavates among 
the pebbles. It is rarely found in warm streams or ponds, and when 
it does occur in such situations is extremely apt to show that this 
unusual habitat has had eft'ect on its structural character. In its eff'ort 
to secure its favorite conditions of water, temperature, etc., it is led 
to ascend the streams, and although this ascent is doubtless made slowly 
and the attempts at ascent are often stopped or seriousl}' checked by 
extensive rapids or heav^^ floods, it is nevertheless almost a certainty 
that through this habit the animal has gone to the very headwaters of 
many a mountain stream and in favorable seasons has crossed the 
■ iShaler, Mem. Bost. Soc. Nat. Hist., II, 1875, pp. 862, 363. 
^Mem. Mus. Comp. Zool., X, No. 4, 18S5, p. 41. 
•■'Proc. U. S. Nat. Mus., XX, 1898, p. 047. 
234 PROCEEDINGS OF THE NATIONAL MUSEUM. vol xxv. 
divide and reached the source of some other streams. As in Viroinia, 
West Virginia, Kentucky, Tennessee, and Indiana many of the small 
streams have their sources in cave streams it is easy to understand that 
C hartoni is of common occurrence in the caverns of the region. I 
have observed and collected the species in several caves in Indiana and 
Kentucky in company with C. pellucidus and have found it abundant 
in several caves in Virginia and West Virginia where C. 2>dh(cidu>< is 
unknown. In one of the latter caves I collected an albinistic specimen 
which is quite indistinguishable from others from the same locality 
now that the alcohol has bleached them, and I have seen similar speci- 
mens in localities where there were no caves. 
A review of the characters peculiar to C. hartoni tenebrosns, for by 
that name the cave-dwelling form may be distinguished, shows that 
there is a tendency in them to approach the characteristics of 0. pellu- 
cidus. At tirst thought it seems as if this might be due to interbreed- 
ing, but there are some difficulties in the way of such an explanation. 
In the tirst place the species exist in the Mammoth Cave in nearly 
equal numl)er, and the females of both have been collected while in the 
egg-bearing state. The ova of C. hartoni are large, those of C. 2)eUii- 
cidus are small, and no \ ariation in the size of the eggs such as would 
probably result from crossing has been observed. The females of C. 
hartoni., and the males as well, will average much larger than C. jpellu- 
cidus and are reported by the guides to kill and eat the blind species, 
a habit that, to say the least, would hardly be conducive to extensive 
crossing of the two species. CkiynharuH hartoni and C. ^^Mveidus are 
perfectly distinct species and could, without much straining of facts, 
be regarded as generically distinct. The greatest diti'erences are found 
in the structure of the sexual organs, and in a group which exhilnts 
such marked specific variation in these organs it seems extremely 
proba})lc that there is a reason for such differences, and that between 
species so unlike interbreeding would be extremely difficult if not 
impossi))le. There are known in the United States three other species 
of blind cave-inha])iting crayfishes and, while they undoubtedly have 
acquired their characters independently, they all resemble C. ]}elhicidus 
(juite closely. Slenderness of body and appendages, and length of 
antennii? are as characteristic of them as is the loss of eyes and color. 
They are conditions brought about by their environment. C. lyellu- 
cidus alone is characterized by excessive spininess, which evidently is 
either a condition inherited from its ancestors or one which has been 
developed in response to the peculiar conditions obtaining within its 
habitat. It will be seen, therefore, that C. hartoni tenehroHUH resembles 
all the blind species in the reduction in size of the eyes, and the increase 
in size of the antennas and the form of the body, moreover there is 
indication (as shown by its spininess) of its having responded to the 
peculiar conditions of Mammoth Cave just as C. pellucid as has. 
NO. 1285. FA UNA OF MAMMOTH CA VE—IIA Y. 235 
These conditions point to the conclusions: First, that O. hartoiil tene- 
hi'osus is a permanent resident of Mammoth Cave; second, that it has 
lived there long- cnoug'h to have diverged markedly from its relations 
on the surface; third, that it has been affected not only by the general 
spelean conditions, but those peculiar special conditions of Mammoth 
Cave; fourth, that it is not the ancestral type from which C. i-xjlluci- 
(his has sprung; fifth, that the two species are proba})Iy to a great 
degree inimical to each other, and, sixth, that the idea that the two 
species interbreed is an erroneous one. 
That specimens have been taken, as I was told at the cave, which 
were quite white but otherwise like C. hartoni fenehrosus, I do not 
doubt, but I regard such individuals as albinos. 
Kegarding the relationship of O. pellncidus testi Hay, I will say 
that so far as is known this subspecies is found in a very small area 
in Indiana at the very northern limits of the range of 0. •pelhicidtis. 
C. hartoni occurs in the same cave, but it does not resemble the blind 
species in any wa}', and has not even characters b}^ which we can mark 
it as a permanent resident. Were the conditions reversed and C. 
hartoni tenelyro-ms found anywhere in company with C. pellucidus 
testi there might be some grounds for regarding them both as possi- 
ble intermediates between C. pellucidus and C. hartoni^ but under 
conditions as they exist such a view is untenable. 
The surface inhabiting individuals of C. hartoni from the neigh- 
borhood of Mammoth Cave are plainly the stock from which the cave- 
inhabiting individuals have descended. In proportions of the body, 
outline, etc., they agree with the cave variety and differ very mark- 
edly from the varieties of C. hartoni found in Indiana and Tennessee. 
CAMBARUS DIOGENES Girard. 
In a collection received from Mr. Edward Hawkins, one of the 
guides at the cave, there were eight specimens of this species, includ- 
ing females and males of both forms. They agree in shape of rostrum 
and form of chelipeds Avith specimens from Indiana, the former having 
thickened and quite strongly converging margins; the chehe are short 
and broad and the movable finger is rather deepl}^ excavated at the 
base. 
CAMBARUS PROPINQUUS Girard. 
A few small specimens which appear to l)elong to this species were 
obtained from pools and shallow chaiuiek along Green River. 
CAMBARUS RUSTICUS Girard. 
A large number of small individuals of this species were collected 
in Green River l)etween Manmioth Cave and Ganters Cave. Almost 
all the males were in the second form. They differ from the typical 
C. rasticas slightly in the g-reater development of spines, those of the 
280 rnncEEDixas of the national 3fCSEC}f. vol. xxv. 
postorbital ridges and sides of the carapace, as well as the lateral 
spines of the rostrum, being strong and prominent, the branchiostegian 
spine is small but quite evident, and the tip of the rostrum is not 
upturned. In one male (Form I) the anterior segment of the telson is 
trispinose on each side. The excessive spininess is doubtless due to 
the immaturity of the specimens. 
CAMBARUS PUTNAMI Faxon. 
This species was found in abundance in the shallow side channels of 
Green River in company with 61 rusticus. Only second-form males 
and females were collected. In the series quite a variation in the form 
of the ro.strum is observable; the margins in some cases being rather 
strongly convergent, in others nearly parallel. In almost every case 
the chelie of the luale have the lingers slightly gaping at the base.