AND CLASSIFICATION OF THE FOSSIL REIHTLJA. 
285 
no ordinal characters to separate the Cotylosauria from tliat group. The pterygoid 
bones are similarly expanded ; the vacuities of the skull which can he com])ared are 
similarly placed; the quadrate bone appears to be similarly excavated in the auditoiy 
region. 
The description of the palate in Empedias is unintelligible when compared with 
the figures, for, although the pterygoid bones may be identified by their posterior 
position and by meeting the quadrate, as well as by the downward direction of their 
external borders, they are described as the palatines. The median bone in front of 
them is termed the vomer, and said to carry two rows of small conical teeth. This 
bone is stated to be separated from the maxillary by a groove, which is represented 
in the figure. Hence, the pterygoid bones and vomer are the only elements of the 
palate described, excepting the greatly expanded palatine plates of the maxillary ; and 
I therefore infer that the palatine bones must have occupied the posterior part of the 
groove between the pterygoid, vomer, and. maxillary bones. If the palatines are thus 
lost and absent, the skull would still have points in common with the Anomodont 
group, though the absence of a median vacuity, defined by the pterygoids and 
palatines, is a remarkable difference ; but it is a character shared by the PlacodouAia, 
and by the Endothiodontia—supposing the latter group to be distinct from the former, 
wdiich has yet to be established. The figure which Professor Cope has given of the 
skull of Naosauras establishes a well developed maxillary dentition, but differs in 
remarkable characters from the Dicynodontia in the conditions and relations which 
are attributed to the quadrate and squamosal bones ; but they do not differ from 
the Dicynodontia more than do the Pareiasauria, or the Placodontia, hardly more 
than the Theriodontia. On the evidence of the skull I am led to regard the Cotylo¬ 
sauria as intermediate between the Placodontia and the Theriodontia, and the Pelyco- 
sauria, in so far as it is possible to judge from the fragment of skull of Naosaurus 
representing it, is intermediate between the Gennetotheria and the Placodontia. 
Comparison of Anomodontia and Protorosauria. 
There is no evidence of close affinity between these groups which would at present 
justify their association under one ordinal type, yet their relation to each other 
appears to be closer than has hitherto been supposed. The pelvis of Protorosaurus 
is essentially intermediate between that of Ornithosaurs and Anomodonts. The limb 
bones are more slender than in any known Anomodont, but the somewhat Mammalian 
character of the tarsus, if unknown in the Anomodontia, appears to be paralleled in 
the American animals whicli Professor Cope names Pelycosauria. Although the 
evidence is very imperfect and inconclusive, I am disposed, from a cast of the 
Freiberg specimen of Protorosaurus which Dr. Woodward has obtained for the 
British Museum, to think that the scapular arch in that specimen probably includes 
pre-coracoid elements, and may be constructed upon the Anomodont plan. The 
