462 Mr. C. T. Regan on the Fishes of 
Mr. Miller, in speaking of M. corneri, says : — " The characters 
by which the fossil is distinguished from M. sandayensls are 
less apparent than those separating the two living Orkney 
species " ; but if the analysis of the characters of the group 
given above be correct, it is precisely with 31. sandayensis 
that our fossil has least to do. 
LVI. — The Fishes of the San Juan River, Colombia . 
By C. Tate Regan, M..A. 
(Published by permission of the Trustees of the British Museum.) 
Dr. H. G. F. Spurrell has recently made an excellent 
collection of fishes in the Condoto, a tributary of the San 
Juan, a river of the Pacific slope in S.W. Colombia, and has 
presented them to the British Museum. Three years ago a 
series of fishes from the San Juan and its tributaries, 
collected by Mr. G. Palmer, was acquired by the Museum. 
These collections are rich in novelties, and, except for a 
few species recently described by Kigenmann (Indiana Univ. 
Studies, 1912, no. 8), our knowledge of the fish-fauna of 
this river-system is based on them. 
Characida?. 
1. Lebiasina multimaculata, Bouleng. 
R. Condoto [Palmer, Spurrell). 
2. Piabucina aureoguttala, Fowler. 
R. Lisa and R. Tamana [Palmer)* 
3. Brycon striatulus, &ner. 
R. San Juan [Palmer). 
4. Brycon oligolepis, sp. n. 
Depth of body 3 to 3^ in the length, length of head 3? to 
4^. Snout nearly as long as or a little longer than diameter 
of eye, which is 3 to 4.^ in length of head ; interorbital 
width 2i to 3. Maxillary extending to below anterior part 
or middle of eye; lower jaw shorter than upper. 13 or 14 
gill-rakers on lower part of anterior arch. 44 to 48 scales 
in lateral line, 8 or 8^ from origin of dorsal to lateral line, 
the San Juan River, Colombia. 4G3 
3| to 1 \ thence to base of pelvics. Dorsal 11-12 ; origin 
behind base of pelvics : longest ray about -| length of head. 
Anal 29-32 j origin below last rays of dorsal ; edge straight 
or slightly emarginate. Pectoral not or barely reaching 
pelvics, which sometimes reach anal. Silvery ; a black spot 
at base of caudal; fins dusky, with paler edges. 
Nine specimens, np to 220 mm. in total length, from the 
llio Condoto (Spurrell) and Western Ecuador (Rosenberg). 
B. moorei } Steind., from the Magdalena Kiver, is near this 
species, but has more numerous scales. B. atricaudatus, 
Kner (B. scapula/ is, Fowler), from W. Ecuador, differs in 
the same respect and also in the larger head. 
5. Creagrutus leuciscus, sp. n. 
Depth of body 3 to 3^ in the length, length of head 3| 
to 4. Snout shorter than diameter of eye, which is 3 in 
length of head and nearly equal to interorbital width. 
Maxillary extending to below anterior \ of eye ; lower jaw 
the shorter. 10 gill-rakers on lower part of anterior arch. 
Lateral line complete, of 35 or 36 scales ; 4 or 4i from 
origin of dorsal tin to lateral line, 3 thence to base of pelvic. 
Dorsal 10 ; origin above insertion of pelvics, nearer end of 
snout than base of caudal. Anal 14-15, emarginate. Pec- 
toral not quite reaching pelvics, which extend to vent or 
origin of anal. Olivaceous ; a bluish-silvery lateral band ; 
no humeral or caudal spots ; fins immaculate. 
Three specimens, 55 to 80 mm. in total leugth, from the 
K. Lisa {Palmer) and the K. Condoto {Spurrell). 
Xenurociiarax, gen. nov. 
Near Deuterodon, differing in that a scaly flap extends on 
the caudal tin, covering a pocket opening downwards, ending 
in a huge triangular scale carrying the lateral line nearly to 
the end of the middle caudal rays, and with its lower half 
marked with numerous vertical striations. 
G. Xenurociiarax spurreUii, sp. u. 
Depth of body 3^ in the length, length of head \\. 
Snout shorter than diameter of eye, which is 3 m length of 
head anil equal to interorbital width. Teeth of outer series 
of pnemaxillaries tricuspid, with weak lateral cusps, 2 teeth 
on one side. '■) on the other ; inner pnemaxdiary teeth with 
3 strong cusps and some times an additional pair of eusps, 4 
teeth on each side ; anterior mandibulary teeth similar to 
464 Mr. C. T. Regan on the Fishes of 
and opposed to inner prsemaxillary series, 4 on each side, 
the fourth considerably smaller than the others and leading 
to the small lateral teeth ; maxillary extending to below 
anterior j of eye, proximally with 1 or 2 small teeth. 
Second suborbital completely covering cheek. 38 scales in 
lateral line, 5^ from origin of dorsal to lateral line, 5 thence 
to base of pelvics. Dorsal 10 ; origin behind base of pelvics, 
slightly nearer end of snout than base of caudal. Anal 32 ; 
origin a little behind middle of dorsal ; a scaly sheath at its 
base ; third to fifth and ninth to thirteenth rays armed with 
series of hooks. Pectoral extending to pelvics, latter to 
origin of anal. Caudal forked. Olivaceous; a bluish-silvery 
lateral band ; no humeral or caudal spots ; fins immaculate. 
■ A single specimen, 57 mm. in total length, from the 
Condoto (Spurrelf). 
7. Bryconamericus rubricauda, sp. n. 
Depth of body 2^ to 3 in length, length of head 3| to 4. 
Snout shorter than diameter of eye, which is 2\ to 2| in 
length of head, equal to or greater than interorbital width. 
Maxillary extending to below anterior ^ of eye. Second 
suborbital covering cheek, its greatest width from § to as 
long as eye. Scales 34 to 38 in lateral line, 5 or 6 from 
origin of dorsal to lateral line, 4 or 5 thence to base of 
pelvics. Dorsal 10-12 ; origin behind base of pelvics, equi- 
distant from anterior part of eye and base of caudal ; longest 
ray a little shorter than head ; free edge straight or a little 
convex. Anal 30-33; origin below end of dorsal; a scaly 
sheath at its base. Pectoral extending to pelvics, which 
reach origin of anal. Caudal scaly at base only. Oliva- 
ceous ; a bluish-silvery lateral band ending in a blackish 
caudal spot ; base of anal and proximal part of caudal lobes 
brilliant orange. 
Eight specimens, 35 to 70 mm. in total length, from the 
Rio Condoto [Palmer, Spurrell). 
8. Bryconamericus juanensis, sp. n. 
Depth of body 2i to 3 in length, length of head 4 to 4^. 
Snout shorter than diameter of eye, which is 2^ to 2§ iu 
length of head, equal to or greater than interorbital width. 
Maxillary extending to below anterior margin or \ of eye. 
Second suborbital covering cheek, its greatest width ^ to § 
diameter of eye. Scales in lateral line 35 to 37, 6 or 7 from 
origin of dorsal to lateral line, 5 or 6 thence to base of 
pelvics. Dorsal 11; origin behind base of pelvics, nearly 
the San Juan River, Colombia. 4G5 
equidistant from end of snout and base of caudal, longest 
ray as lung as head ; free edge straight. Anal 29-32 ; 
origin below or just behind end of dorsal ; a Scaly sheath at 
its base. Pectoral extending to pelvies, which reach' vent. 
Caudal scaly at base only. Olivaceous ; a bluish-silvery 
Lateral band ending iu a blackish caudal spot. 
Ten specimens, 45 to 90 mm. in total length, from the 
Rio Condoto (Spurreli) and the Rio San Juan and Rio 
Tarn an a (Palmer). 
This species has a larger eye and narrower suborbitals 
than the preceding and usually more scales in a transverse 
series. Both have the dentition characteristic of the genus, 
the pnemaxillaries with an inner series of -1 teeth on each 
side and an outer series of 5, the second and fourth internal 
to the others. 
9. Bryconamericus scleroparius, Regan. 
R. San Juan {Pal/tier). 
10. Hyphessobrycon condotensis, sp. n. 
Depth of body 2£ to 2| in length, length of head 3jfc. 
Snout much shorter than diameter of eye, which is 2j in 
length of head ; interorbital width 3. Maxillary extending 
to below anterior \ of eye ; a naked space between second 
suborbital and praeopercle. 33 to 35 scales in a longitudinal 
series, 10 to 15 in lateral line, 7 or 8 from origin of dorsal 
to lateral line, 5 or 6 thence to base of pelvics. Dorsal 11 ; 
origin nearly equidistant from end of snout and base of 
caudal; longest ray as long as head. Anal 28-30 ; origiu 
below posterior part of dorsal ; a distinct scaly sheath at 
base of anterior rays. Olivaceous ; a dusky lateral stripe 
posteriorly ; a vertically expanded dark humeral spot, a 
second dark spot behind it ; no caudal spot ; dorsal immacu- 
late ; base of anal and caudal lobes bright orange. 
Several specimens, 30-10 mm. iu total length, from the 
Rio Condoto (Spurreli) and the Rio San Juan (Palmer). 
11. Astyanax ameus, Gunth. 
R. San Juan (Palmer). 
12. Nematobrycon palmeri. Eigcnm. 
R. Condoto (Palmer, Spurreli) ; R. San Juan (Palmer). 
466 Mr. C. T. Regan on the Fishes of 
13. Gephyrocharax chocoensis, Eigenm. 
14. Parastremma sadina, Eigenm. 
15. Rceboides guatemalensis, Giinth. 
R. San Juan [Palmer). 
Gastropelecidse. 
16. Thoracocharax brevis, Eigenm. 
R. San Juan {Palmer). 
Xiphostomatidaa. 
17. Luciocharax strialus, Bouleng. 
R. San Juan (Palmer). 
Anostomidae. 
18. Curimatus lineopunctatus, Bouleng. 
R. Tamana (Palmer). 
Sternarcliidae. 
19. Sternopygus csquilabiatus, Humboldt. 
R. Condoto (SpurreH) . 
Gymnotidae. 
20. Gymnotus carapo, Linn. 
R Condoto (Spurred). 
Pimelodidae. 
21. Pimelodella eutcenia, sp. n. 
Depth about 5^ in the length, length of head 4 to 4§. 
Diameter of eye 3g to 4£ in length of head, nearly equal to 
interorbital width. Head 1£- as long as broad; snout a 
little longer than postorbital part of head ; width of mouth 
^ width of head ; maxillary barbel extending to middle of 
anal fin. Dorsal 1 7 ; spine nearly smooth, i to § length of 
head ; adipose fin 3^ to 3^ in length of fish. Anal 11-12. 
Pectoral spine | length of head ; inner edge weakly denticu- 
lated. Pel vies inserted behind dorsal, not reaching anal. 
the San Juan R'irer, Colombia. 167 
Caudal forked. Greyish ; a strong blackish stripe from 
snout through eve to base of caudal fin ; posterior half of 
each Luterradial membrane of dorsal dusky. 
Five specimens, 75 to 145 mm. in total length, from the 
Rio Condoto (Spurrell) and the ELio Sipi (Palmer). 
This species is related to P. buckleyi, Bouleng., from the 
Amazons of Ecuador, which has shorter barbels, a longer 
adipose fin, a different coloration, &c. 
22. Pimelodella yrisea, Regan. 
R. Sau Juan (Palmer). 
23. Rhamdia wagneri, Guuth. 
R. Sau Juan (Palmer). 
Nannorhamdia, gen. nov. 
Intermediate between Rhamdia aud Naiutoglanis, differing 
from the former in the absence of dorsal aud pectoral spines, 
the vestigial occipital process, the more posterior position of 
the dorsal fin, and the shorter anal fin ; from the latter in the 
less depressed head, the eyes lateral and with free margins, 
the dorsal fin above instead of behind the pelvics, the caudal 
forked instead of truncate. 
24. Nannorhamdia spurreUii, sp. n. 
Depth of body 6 in the length, length of head 4i. 
Diameter of eye 2 in length of snout, G in length of head, 
li hi in terorbital width. Lower jaw the shorter. Maxillary 
barbel extending to end of pectoral fin. Dorsal 7 ; origin i 
as distant from end of snout as from base of caudal ; adipose 
fin as long as its distance from dorsal. Anal 9. Pectoral \ 
length of head, not reaching pelvics, which are inserted 
below middle of dorsal and do not nearly reach anal. Vent 
a short distance behind base of pelvics. Greyish ; a dusky 
lateral stripe. 
A single specimen, 70 mm. in total length, from the 
R. Condoto (Spurrell). 
25. Pseudopimelodus transmontanns, sp. n. 
Skin with papillae or filaments, which are always evident 
above the pectorals. Depth of body \\ to 6 in the length, 
Length of head 3to3£. Head nearly as long as broad. 1 >i i- 
nieter of eye 1,' to 18 in length of head, interoeular width 
468 Mr. C. T. Regan on the Fishes of 
2 to 2^, length of snout 3 to 3f . Jaws equal anteriorly ; prse- 
maxillary band of teetli with a pointed process at each end; 
maxillary barbel extending to operculum or basal part of pec- 
toral. Occipital process separated by an interspace from basal 
bone of dorsal spine. Dorsal I 6 ; spine smooth, \ to § length 
of'head. AnallO. Pectoral spine ^ to | length of head, serrated 
on both edges, the posterior teeth usually the stronger, in 
length not much less than the width of the spine ; clavicular 
process short, its upper edge about equal to diameter of eye. 
Pelvics not reaching anal. Caudal rounded in adult, in young 
upper lobe produced and pointed. Adults uniformly dark 
greyish ; young with a pale transverse bar from base of one 
pectoral fin to the other, a series of 4 pale spots along the 
back, respectively in front of and behind dorsal tin, on and 
behind adipose fin, and 3 larger pale spots along each side. 
Caudal with small dark spots, blackish at base and often 
crossed by a dark bar posteriorly ; other fins either entirely 
blackish, or with a pale margin, or pale with a blackish bar. 
Nine specimens, 60 to 250 mm. in total length, from the 
Condoto (Spurrell), the San Juan and the Tamana (Palmer), 
and the Durango, W. Ecuador {Rosenberg) . 
Related to P. villosus, Eigenm., from British Guiana. 
Pygidiidae. 
26. Pygidium unicolor, sp. n. 
Depth of body 7 in length, length of head 6. Head as 
broad as long. Diameter of eye 12 in length of head or 3 in 
interocular width ; eyes well in advance of middle of head, 
close behind nostrils. Barbels as long as head. Doz-sal 8-9, 
with 5 or 6 branched rays, rounded ; origin above or a little 
in advance of vent, 1| as far from end of snout as from base 
of caudal. Anal 7, with 4 branched rays; origin below last 
rays of dorsal. Pectoral filament -£ to as long as head, 
branched rays § length of head. Pelvics covering vent. 
Caudal subtruncate. Coloration uniform. 
Two specimens, 80 and 85 mm. in total length, from the 
Condoto (Spurrell). 
27. Pygidium spilosoma, sp. n. 
Depth of body 7 to 8 in length, length of head 6 to 6|. 
Head longer than broad. Diameter of eye 10 to 12 in 
length of head, 2^ to 3 in interocular width ; eyes very 
slightly in advance of middle of length of head, their distance 
from posterior nostrils g or y of length of head. Maxillary 
the San Juan River, Colombia. - 4G9 
barbel nearly as long as bead, extending to basal part of 
pectoral. Dorsal 9, with 6 branched rays ; free edge 
straight ; origin a little in advance of vent, 1| as far from 
end of snout as from base of caudal. Anal 7, with 4 branched 
rays ; origin a little behind end of dorsal. Pectoral filament 
as long as head, branched rays 5 to f length of head. 
Caudal truncate or slightly cmarginate. Yellowish, with 
dark brown spots on body and fins ; young with a dark 
lateral band. 
Three examples, 130 to 250 mm. in total length, from the 
Rio Sipi and Rio Tamana (Palmer). 
28. Pygidium taenia, Kner. 
R. Sipi and R. Tamana {Palmer). 
Loricariidae. 
29. Lasiancisfrns caucanus, Eigenm. 
R. Condoto (Spurrell). 
30. Hemiancistrus mayoloi, Eigenm. 
31. Hemiancistrus Iwlostictus, sp. n. 
Depth of body 4^ in the length, length of head 3^. Head 
as broad as long, its depth If in its length, length of snout 
If, diameter of eye 7, interorbital width 2jf. Length of 
barbel equal to that of mandibular^ ramus or to diameter of 
eye. Interoperclc freely movable, but with only 2 or 3 very 
short spines. Occipital plate with median ridge, bordered 
by a single scute; temporal plates keeled. Scutes keeled, 
2f> in a longitudinal series ; abdomen in great part naked, 
scaly in front and at the sides. Dorsal I 7; base nearly as 
long as distance from caudal; first ray longer than head, 
reaching adipose fin when laid hack : last nearly f_ as long. 
Anal I 1. Pectoral spine extending to anterior -\ of pel vies. 
Caudal emarginate. Caudal peduncle nearly 3 times as long 
as deep. Head, body, and fins covered with round dark 
spots. 
A single specimen, 180 mm. in total length. 
This speeies is mar H. annectens, Regan, from Western 
Ecuador, but differs in the deeper form, the larger dorsal 
fin, the very small interopcrcular spines, &c. 
32. Pseudancistrus sctosit.-t. Bouleng. 
R. Tamana (Palmer). 
470 * Mr. C. T. Regan on the Fishes of 
33. CJuetostomus palmeri ', Regan. 
R. Tamana (Palmer). 
34. Chatostomus Upturns, Regan. 
31. Taraana (Palmer) ; R. Condoto (Spurrell). 
35. Cha>tostomus paucispinis, Regan. 
R. San Juan (Palmer). 
36. Chcetostomus margin atus i Regan. 
R. Condoto (Spurrell). 
37. Ancistrus centrolepis, sp. n. 
Depth of body 5 in the length, length of head 2f . Breadth 
of head 3^ in its length, depth 2, length of snout 2, diameter 
of eye 7 to 8, interorbital width 2. Length of mandibular 
ramus 3^ to 3^ in interorbital width. Snout with tentacles, 
its upper surface nearly covered with bony plates, leaving 
only a narrow naked margin ( ? ). fnteroperculum with 30 
or 32 spines; longest nearly § length of head. 24 scutes in 
a longitudinal series ; lateral scutes with the middle 2 or 3 
series of spinules enlarged, ending in quite strong spines at 
the posterior edge of each scute. Dorsal I 7 ; base as long 
as its distance from tip of spine of adipose fin ; first ray | or 
| length of head, last reaching adipose fin when laid back. 
Anal 3 4. Pectoral spine reaching anterior ^ or middle of 
pelvics. Caudal obliquely truncate. Caudal peduncle 2| to 
2^ as long as deep. Uniformly blackish. 
Two specimens ( ? ), 350 and 395 mm. in total length, the 
larger from Choco, R. San Juan (Palmer). 
This species is near A. hoplogenys, differing in the structure 
of the scutes and the narrower naked margin of the snout. 
38. Loricaria magdalence, Steind. 
R. San Juan (Palmer) ; R. Condoto (Spurrell). 
39. Sturisoma tamanee, Regan. 
R. Tamana (Palmer) ; R. Condoto (Spurrell). 
40. Sturisoma panamensis, Eigenm. 
31. San Juan (Palmer) ; 31. Condoto (Spurrell). 
the San Juan [liver, Colombia. 471 
41. Cyclopiuni cirratum i Regan. 
II. Condoto (Palmer). 
12. Cyclopium ventrale, Eigenm. 
Probably a synonym of C. cirratum. 
Pceciliidae. 
43. Rivulus elegans, Steind. 
R. Condoto (Palmer, Spurrell). 
44. Gambusia nigroventralis, Eigenm. 
Perhaps a synonym of G. episcopi, Steind. 
45. Gambusia caudovittata, sp. n. 
Depth of body equal to length of head, 4 in length of fish. 
Diameter of eye 3 in length of head, interorbital width 24. 
Mouth small ; an outer series of strong curved conical teeth 
especially prominent in upper jaw. Dorsal 8 j origin equi- 
distant from posterior part of eye and base of caudal. 
Anal 9 ; origin a little in advance of dorsal. Pectoral i 
length of head. Caudal rounded. 30 scales in a longitu- 
dinal series. Olivaceous ; a dusky bar across posterior part 
of caudal. 
One specimen, a female, 25 mm. in total length, from the 
Rio Condoto [Spurrell). 
Belonidae. 
46. Belone fiuviatilis, Regan. 
R. Condoto (Spwrell). 
Cichlidae. 
47. Cichlosoma (JEquidem) caruleopunctatum, 
Kner & Steind. 
R. Condoto and R. Tamana (Palme?'). 
48. Cichlosoma (JEquidens) biseriatum, sp. n. 
Depth of body 2£ to 2£ in the length, length of head 2| 
to 3. Snout as long as or shorter than diameter of eve, 
which is 3 to 3£ in length of head and about equal to inter- 
orbital width Jaws equal anteriorly; maxillary extendin 
- 
472 On the Fishes of the San Juan River, Colombia. 
to below anterior margin of eye ; depth of prseorbital 4 to 
5 diameter of eye ; cheek with only 2 series of scales, rarely 
a third series of 2 to 4 scales running upwards and back- 
wards from behind angle of mouth to below eye ; prseopercle 
scaleless ; 5 or 6 gill-rakers on lower part of anterior arch. 
23 to 26 scales in a longitudinal series, 3 from first dorsal 
spine and 1 or 1| from first soft ray to lateral line, 8 rows 
below lateral line. Dorsal XV 9-10; fifth to twelfth spines 
subequal, ^ length of head ; last spine § length of bead ; 
soft fin pointed, extending to anterior part or middle of 
caudal. Anal III 7-8. Dorsal and anal scaleless. Pectoral 
nearly as long as head, extending to origin of anal ; pelvics 
reaching anal. Caudal rounded. Caudal peduncle ^ to § 
as long as deep. Uniformly dark or with dark longitudinal 
stripes or series of spots along the rows of scales; paler 
specimens with cross-bars, a lateral blotch, and a small spot 
at base of caudal ; a blackish spot or ocellus on dorsal fin 
between tenth and twelfth spines : often another in front 
of and another behind it ; dorsal with pale edge and dark 
intramarginal stripe ; soft dorsal spotted ; lower fins dark- 
edged. 
Seven specimens, the largest 80 mm. in total length, from 
the Rio Condoto (Spurrell). 
49. Cichlosoma (Par ape tenia) airomaculatum, Regan. 
R. Condoto (Palmer, Spurrell) and R. San Juan (Palmer). 
50. Geophagus pellegrini, Regan. 
R. San Juan (Palmer); R. Condoto (Spurrell). 
Atherinidae. 
51. Thyrina guatemalensis, Giinth. 
R. Condoto (Spurrell). 
Gobiida?. 
52. Philypnus maculatus, Giinth. 
R. San Juan (Palmer). 
53. Eleotris picta, Kner & Steind. 
- R. San Juan (Palmer). 
On Gemma, Parastarte, and Psephidia. 473 
54. Chonophorus transandeanus, G until. 
R. Condoto (Spurrelf). 
Symbranchidae. 
55. Symbranchus marmoratus, Bloch. 
R. Condoto (Spurrell). 
LVII. — On the She/Is knoion as Gemma, Parastarte, and 
Psephidia. By A. J. Jukes-Beowne, B.A., F.R.S. 
These small shells are aberrant members of the VeneridaB, 
which have sometimes been regarded as independent genera 
and sometimes as subgenera of Venus or Chione. A recenl 
examination of specimens under the microscope has disclosed 
the fact that several mistakes have been made with regard 
to their internal characters, and has also revealed some 
features which seem to have escaped notice. I propose, 
therefore, to give a more complete and accurate account ol 
these shells, and to indicate a speeies which has been referred 
to Psephidia (=Psephis), but which differs in so many 
particulars that it must be regarded as a distinct subgenus, 
and, as such, must receive a new name. 
1. Gemma, Deshayes. 
This little shell was first described as Venus gemma by 
J. S. Totten in 1834*, and was for a long time supposed to 
have only two teeth in the right valve, all the text-books 
copying Deshayes's erroneous statement to that effect, 
although it is quite clear that Totten and other American 
conchologists knew quite well that there were three teeth in 
each valve. 
The three teeth of the right valve are fairly well shown in 
Totten's figure, and he described the dentition as follows: — 
"Teeth divergent, the medial tooth of each valve stout and 
triangular, the anterior tooth of the right and the posterior of 
the left valve thin and not easily recognized." The shell 
was accepted as a Venus by Gould in 1841 f, who described 
* ' American Journal of Science,' vol. xxvi. p. 366 (New York, 1834). 
t Report mi Invert, of Massachusetts, p. B8, li-r. 51. 
Ann. (& M<i<j. N. Hist. Ser. 8. Vol. xii. ! 3 1