204 Mr. G. A. Boulenger on some Jurassic and 
liaving ceased to develop at an early stage, and being re- 
modelled after the fashion of the dipterous larvae which we 
have been discussing, might have acquired the power of 
psedogenetic reproduction. I readily admit that our hypo- 
theses are somewhat many in number ; but there is not a 
single one among them which has not been actually observed 
in the Arthropod phylum itself, and more frequently in combi- 
nations. Whether the leg-stumps of the Tardigrades have 
arisen by degeneration from Arthropod appendages of their 
ancestors, or whether they may be new formations like the 
pro-legs and claspers of the caterpillars, is a question which 
is difficult to decide. Its solution, however, be it as it may, 
needs to alter nothing in the whole conception. 
If we once more briefly sum up the points of agreement 
between the Tardigrades and greatly modified Tracheate 
larvEe, somewhat of the type of the maggots of Cecidomyia^ 
we find: — absence of a head, chitinous stylets in the oesopha- 
geal tube, absence of any ciliated epithelium and of a dermal 
muscle-sheath, musculature broken up into isolated cords, 
supra-cesophageal ganglion and ventral ganglion-chain, 
simple structure of the sexual organs, and, lastly, Malpighian 
vessels. The differences depend upon further advanced 
degeneration of the Tardigrades, and include : — small number 
of the ganglia (disappearance of the parts of the suboesophageal 
ganglion), smooth musculature, absence of trachese and circu- 
latory organs, and the probable reduction of the one germ- 
gland. As new formations we may perhaps regard the 
efferent duct of the sexual organs and^ at any rate, the leg- 
stumps, if these are not an ancestral character. 
Embryology as yet affords us no explanation ; besides the 
development need no longer be of the typical Arthropod type, 
but may have secondarily undergone great modifications. 
XXX. — On some neicly-descrihed Jurassic and Cretaceous 
Lizards and lihynciioctphalians. By G. A. BoULENGER. 
In a paper published two years ago (2), whilst dealing with 
a few points in the osteology of Heloderma and the systematic 
position of that genus of lizards, I ventured to express some 
views on the probable phylogeny of the order Squamata, 
which comprises the existing group of true lizards, chame- 
leons, and snakes. I pointed out that the Cretaceous lizard 
Hydrosaurus lesinensis^ regarded by some authors as a member 
Cretaceous Lizards and Rhynchocephalians. 205 
of the family Varanidas, agreed, so far as could be judged from 
the figures published by Kornhuber, with Owen's Dolicho- 
sauriis, and that the suborder Dolichosauria might prove to 
be the ancestral group from which the Lacertilia, Pythono- 
morpha, and Ophidia evolved. This opinion was founded on 
the archaic condition of the hind limbs and the number of 
cervical vertebra3 ; the presence of the zygosphenal articula- 
tion of the vertebrae, present in all Ophidia and several 
Lacertilia and Pythonomorpha, lent additional support to 
this hypothesis. 
As 1 expected, my views have not had the approval of 
Dr. Baur, who, in a lately published paper on the skull of 
Mosasaurs (1), adheres to his previously expressed opinion 
that the Varanidte, Mosasauridas, and Helodermatidee should 
be grouped together as a suborder " Platynota." 
With regard to the structure of the foot, he denies any 
considerable difference between Kornhuber's Hydrosaurus 
lesinenstSj which I referred to the Dolichosauria, and a true 
Varaiius. But unless he contests the correctness of Korn- 
huber's restoration of the metatarsals and propodials, his 
statement does not refute my interpretation ; the figures 
which I have reproduced (after Marsh and Kornhuber) speak 
for themselves. On the other hand, when he says that he 
has " no hesitation to assume that unguiculated limbs can be 
transformed into paddles with numerous phalanges," I entirely 
agree with him, and do not know that I have ever expressed 
any opinion to the contrary. 
His other argument is that there is no evidence for the 
supposition that the number of cervical vertebrge after having 
increased in the Dolichosauria can have become gradually 
reduced again until the Rhiptoglossan number five was 
reached. If my critic admits, as I believe he does, that the 
Rhynchocephalia are descended from the Stegocephala, which 
have fewer than eight cervical vertebra3, and that the Khipto- 
glossa are only an ultra-specialized branch of the typical 
Lacertilia, he cannot well argue against the probability of 
such a process of increase followed again by a reduction. In 
fact, if he will refer to one of his previous contributions to the 
phylogeny of the Eeptilia, he will find that he has no diffi- 
culty in assuming that the Chelonians, with eight cervicals, 
may have been descended from Plesiosaurians with very 
numerous cervicals, the latter having been, as he himself 
admits, derived from short-necked forms. That he now holds 
" All forms which show a greater or smaller number of 
cervicals [to] have with very little doubt developed from forms 
with eight cervicals " shows that his views have undergone a 
206 Mr. G. A. Boulengcr on some Jurassic and 
considerable change since 1887, when, commenting on Parker's 
discovery of at least fifteen somatomes in the cervical region 
of the embryo of Chelone, he regards the latter author's 
statement, that " This free suppression of segments suggests 
a great secular modification by shortening of a form not 
unlike a Plesiosaur," as a '* proof of the affinity of the Testu- 
dinata and Sauropterygia." What Dr. Baur proves with so 
much assurance on one occasion he himself pretends to dis- 
prove on the next, without even referring to the position he 
has previously taken up. 
Two recently published contributions throw fresh light on 
the Jurassic and Cretaceous Squamata, and suggest some 
further remarks on the subject. 
The first of these contributions is a paper by Gorjanovic- 
Kramberger (5) , who, ignoring my previously published note 
and reasoning from a different point of view, arrives at results 
very similar to mine in dealing with the systematic position 
of some Cretaceous lizai-ds from Dalmatia. 
He describes a new form, Aigralosaurus, which shows 
points of affinity to the Dolichosauria, the Pythonomorpha, 
and the Varanoid Lacertilia, and proposes to establish a group 
named Ophiosauria to comprise the Aigialosauridae and 
Dolichosauridaj. It is needless to observe that the term 
Ophiosauria must be superseded by that of Dolichosauria, 
which is of older standing, although Kramberger appears to 
be ignorant of its existence. His definition of the group is, 
besides, deficient in truly diagnostic characters. 
The Bydrosaurus lesinensis of Kornhuber is incidentally 
dealt with, and the genus Pontosaurus is established for it in 
the family Aigialosauridae, which is stated to be distinguished 
from the Dolichosauridse by the number, 7 to 9, of cervical 
vertebrge. However, it seems clear to me, after reexami- 
nation of the figure given by Kornhuber, that H. lesinensis 
possessed about 15 cervical vertebrae, and I am still at a loss 
to find how it is to be generically distinguished from Doliclio- 
scmrus. But this is a matter which cannot well be dealt with 
without comparing the specimens themselves ; therefore the 
genus Pontosaurus may be accepted provisionally, provided 
it be not identical with Acteosaurus of H. v. Meyer or Adrio- 
saurus of Seeley. 
AigiaIosau7-uSj of which the figure of a nearly perfect 
specimen is given, is a remarkable lizard, with somewhat the 
physiognomy of a Monitor or Varanus, but with the jugal in 
contact with the postfrontal and closing the orbit behind, 
shorter and stouter ribs, and limbs much of the same type as 
in Pontosaurus, although more developed. The quadrate is 
Cretaceous Lizards and Rhynchocephalians. 207 
sliown to differ considerably from tliat of the Varanidre and 
to agree very closely with that of Mosasaurs. Kramberger 
is therefore fully justified in regarding this type as one of the 
orio-inal stock from which the Varanoids and the Mosasaurs 
were derived. 
There are a few points in Kramberger's description which 
need criticism. First, as regards the number of cervical 
vertebras : whilst admitting that, owing to the sternum not 
being preserved, it is difficult to decide which is the first 
dorsal vertebra (taking as such that which bears the first 
sternal rib) , the author assumes that only seven vertebrae are 
to be reckoned as cervicals, his reason being that the scapula 
in his specimen is situated on a line with the fifth to seventh 
vertebrae. In a specimen of Varaiius niloticus wliich I have 
before me I find that the scapula corresponds to the sixth and 
seventh vertebrae, and yet nine cervicals exist ; besides, the 
last cervical is a little shorter than the first dorsal, the differ- 
ence between the two being about the same as represented in 
d. 2 and d. .3 of Kramberger's figure. I would therefore say 
that Aigialosaurus had nine cervical vertebrae, or even ten in 
the event of the atlas having been overlooked. 
A second criticism I have to make is with respect to the 
importance attached by Kramberger to the great development 
of the cervical autogenous hypapophyses of his reptile as 
differentiating it from existing lizards ; for on the five anterior 
vertebree of the Agamoid Physignathus Lesuenrii I find them 
quite as long as in Aigialosaurus^ and other recent lizards 
approach this condition. 
An interesting point in the specimen figured is the presence, 
to Vv'hich, however, no allusion is made in the text, of double 
parapopliyses to the second sacral and the first two caudal 
vertebrge, thus representing the well-known " lymphapo- 
physes " of snakes. On this occasion I would remark that 
DoUo, in a recent contribution, is entirely mistaken when he 
thinks that the lymphapophyses of snakes and apodal lizards 
represent the combined ribs and ha^mapophyses. A glance 
at the skeleton of a viper, to mention no other examples, 
shows that the lymphapophyses may coexist with the paired 
hypapophyses on one and the same vertebra. His statement, 
'* les lymphapophyses ne coexistent jamais sur la meme 
vert^brc, soit avec les cotes, soit avec les haemapophyses," is 
therefore erroneous ; and his deductions, so far as this point 
is concerned, consequently fall to the ground. 
We have so long been ignorant of any undoubted pre- 
Tertiary Lacertilian in the restricted sense, that much 
importance attaches to the desciiption of the Upper Jurassic 
208 Mr. G. A. Boulenger on some Jurassic and 
Euposaurus Thiollierii^ Lortet, wliicli has just appeared in 
Dr. Lortet's splendidly illustrated memoir on the fossil 
reptiles of the Rhone Basin (6). Althoug:!! the fossil is unac- 
countably referred to the Rhynchocephalia, and even to 
the family Sphenodontidge, which, in the French author's 
classification, includes Ilomoiosaurus, there can be no doubt 
that we have here to do with a true lizard, as is evidenced 
by the absence of a quadrato-jugal arch and of a plastron. 
The pleurodont dentition, the absence of supra-temporal 
fossEB, the non-dilatation of the clavicles, are characters which 
a])proximate Euposaurus to the Anguidae. The interclavicle 
(" sternum " of Lortet) is unfortunately not preserved. A 
curious oversight is noticeable in the description of this lizard, 
the fifth toe being described as the hallux, whicli is thus 
stated to be opposable to the other digits, whereas in reality 
the pes does not differ from that of an ordinary lizard. 
Of still greater interest is Lortet's account and figure of 
Pleurosaurus Goldfussii^ H. v. Meyer, likewise referred to 
the Sphenodontidag. It is, however, quite clear that the 
cranial characters are not Rhynchocephalian. The temporal 
arch appears to be essentially of a Lacertilian type and to 
correspond with what is found in the Agamid^e. But the 
structure of the limbs is primitive, agreeing in the tibia and 
ulna and the metatarsals with the Dolichosauria and Protero- 
sauria ; and as the specimens described by H. v. Meyer show 
a plastron in the form of fine riblets, which are, however, not 
preserved in Lortet's specimen, Pleurosaurus should be 
regarded as the type of a distinct order of reptiles, combining 
characters of the Proterosaurian Rhynchocephalia and Squa- 
mata, for which the name Acrosauria, proposed by H. v. 
Meyer in 1860, may be used. 
The number of cervical vertebrse in Pleurosaurus is stated 
by Lortet to be only five. I have to repeat the criticism 
made above respecting Kramberger's AigialosauruSy and to 
add that the first rib-bearing vertebra does not represent the 
atlas ; this vertebra is not even entirely concealed in Lortet's 
specimen. Two small bones visible behind the occiput are, 
in my opinion, the neuroids of the atlas. By further adding 
to the neck the two vertebrae named by Lortet first and second 
dorsal we have eight cervicals instead of five. 
Dr. Lortet's memoir is also rich in information respecting 
the Hhynchocephalian genera Homoeosaurus and Sauranodon 
(which name must yield to the prior Sa.pJiceosaurus) . The 
latter genus was very imperfectly known ; but the beautiful 
figures and the detailed description now published leave little 
to desire, although some important characters shown by the 
Cretaceous Lizards and Rhynchocephalians. 209 
figures are not alluded to in the text. A new family, Saura- 
nodontes, is established by Dr. Lortet for its reception, and 
is chieflj founded on the total absence of teeth and the pro- 
coelous vertebrae. In dealing- with the latter character the 
author curiously contradicts himself, for in the definition of 
the family (p. 29) the vertebral centra are stated to be con- 
cave behind, whilst further on (p. 53) the reverse is described. 
That the latter statement is the correct one is shown by the 
figures on pi. iii. The skull, as in the Rhynchosauridse, has 
no parietal foramen, and the bones described as the posterior 
portions of the parietals appear to be the supra-temporals, 
distinct from the squamosals. 
The position of this new family in the system is indicated 
in the following revised scheme of the classification proposed 
by me in 1891 (3). The Champsosauridaj, first included in 
the Rhynchocephalia vera, are now shifted to the Protero- 
sauria, in accordance with the recent researches of Dollo (4), 
who has shown these reptiles to be related to Proterosaurus. 
Older RHYNCHOCEPHALIA, 
Suborder I. PROTEROSAURIA. 
Each transverse segment of the plastron composed of numerous paired 
pieces. Pubis and ischium plate-like. Fifth metatarsal not modified. 
A. Nasal openings distinct. 
Vertebrae conically excavated at either end, 
with persistent notochord, all with inter- 
vertebral hypapophyses ; limb-bones vpith- 
out condyles ; humerus with entepicondylar 
foramen 1. Paljeohattebiid^. 
Vertebrae fully ossified, cervicals opisthocoelous, 
dorsals biconcave ; no hypapophyses be- 
tween the dorsal vertebne ; limb-bones 
with condyles ; humerus with ectepicon- 
dylar foramen or groove 2. Pkotebosaurid^. 
B, Nasal opening single ; vertebroe fully 
ossified, feebly biconcave ; no hypapo- 
physes between the dorsal vertebrae ; 
humerus with ectepicoudylar groove . . 3. CHAMPSOSAuniDiE. 
Suborder II. RHYNCHOCEPHALIA VERA. 
Each transverse segment of the plastron composed of three pieces, a 
median angulate and a pair of lateral. Pubis and ischium elongate and 
fifth metatarsal modified, as in the Lacertilia. 
A. Jaws toothed ; vertebrae amphicoelous. 
a. Nasal openings distinct ; mandible with 
coronoid process, the rami not united 
by suture. Vertebrae deeply biconcave. 
210 Messrs. T. and A. Scott on some 
Humerus with ectepicondylar and entepicon- 
dylar foramen ; ribs with uncinate pro- 
cesses ; all the vertebrae with iutercentral 
hypapophyses 4. Hattrriid^. 
Humerus with entepicondylar foramen ; ribs 
without uncinate processes ; no hypapo- 
physes between the dorsal vertebrae 5. Ho.ucEJSAuaiDiE. 
b. Nasal opening single. Mandible with- 
out coronoid process, the rami united 
in a solid S3'mphysis ; vertebrae feebly 
biconcave ; no hypapophyses between 
the dorsal vertebrae. Humerus with 
ectepicondylar foramen or groove .... 6. RHyNCHOSAURiD.E. 
B. Jaws toothless. Vertebrae procoelous. 
3Iaudible without coronoid process, the 
rami united in a solid symphysis. Hu- 
merus with ectepicondylar foramen .... 7. Sauranobontid^. 
References. 
(1) Baur, G.— " On the Morphology of the Skull in the Mosasauridae," 
Journ. of Morphol. vii., 1892, pp. 1-22, pis. i. and ii. 
(2) BouLENGER, G. A. — " Notes on the Osteology of Ileloderma horri- 
dum and H. sus^jectum, with Remarks on the Systematic Position 
of the Helodermatidas," Proc. Zool. Soc. 1891, pp. 109-118. 
(3) BouLENGER, G. A. — " On British Remains of Homceosaunis, with 
Remarks on the Classification of the Rhynchocephalia/' t. c. 
pp. 167-172. 
(4) Hollo, L. — " Nouvelle Note sur le Champsosaure," Bull. Soc. G»5ol. 
Belg. v., 1892, pp. 5-53, pis. vi.-viii. 
(5) Gorjanovic-Kramberger, C. — " Aigialosaurus, eine neue Eidechse 
aus den Kreideschiefern der Insel Lesiua, mit Riicksicht auf die 
bereits beschriebenen Lacertiden von Comen und Lesina," Glasnik 
Soc. Hist.-Nat. Croat, vii., 1892, pp. 74-106, pis. iii. and iv. 
(6) LoRTET, L. — " Les Reptiles fossiles du Bassin du Rhone," Arch. 
Mus. Hist. Nat. Lyon, v., 1892, 139 pp., 16 pis. 
XXXI. — On some new or rare Scottish Entomostraca. By 
Thomas Scott, F.L.S., Naturalist to the Fishery Board 
for Scotland, and Andrew Scott. 
[Plates VH. & VIII.] 
Paeartotrogus, gen. no v. (provisional name). 
Anterior and posterior antennae and mouth-organs as in 
Artotrogus^ Boeck, except that the siphon is rudimentary. 
First pair of swimming-feet with both branches two-jointed ;