DESMOSPONDYLUS ANOMALUS 281 



presence of an entepicondylar foramen. It unquestionably belongs in the 

 present genus. 



The University of Chicago collection of Permian vertebrates from 

 Texas and Oklahoma now includes representatives of at least 26 genera, 

 all of which I know more or less well. Five or six of the genera de- 

 scriljed from Texas and Oklahoma, some of them on fragmentary mate- 

 rial, I have so far not identified, though I have seen the t3rpes of several. 

 They are CricotiUus Case, of doubtful validity; Seymouria and Cardia- 

 cepliahis Broili ; Isodectes, Pantylus, and Anisodexis Cope. It is, hence, 

 possible that our genus may be identical with some one of these, but the 

 probability is so slight that I have no hesitation in giving the new generic 

 and specific name to the present specimens. 



The vertebrae, of which there are 20 or more centra and fragmentary 

 arches, in addition to the connected series of 7 or 8, present some extra- 

 ordinary characters — characters which are very suggestive of amphibian 

 affinities, annectant l)etween the rhachitomous and holospondylous types. 

 The centra, coming all of them apparently from the posterior dorsal 

 region and the tail, are short, almost disklike, deeply concave, with a 

 small perforating foramen. The arches are entirely free; the sutural 

 surface for their attachment is extensive, situated on the anterior three- 

 fourths of the centrum and extending downward on the front margin to 

 l^elow the middle. Back of this sutural surface there is a similar beveled 

 surface extending about one-fourth of the length of the centrum, which 

 also reaches down on the posterior side to the middle of the centrum. 

 The arches are very low, with a rudimentary spine only, resembling the 

 arches of Labidosaurus or CaptorJiinus. The zygopophyses are very large 

 and broad, with their surfaces nearly horizontal. Below and back of the 

 anterior zygapophyses there is, on either side, a distinct diapophysis, on 

 the more anterior vertebrae standing out prominently, on the posterior 

 ones a mere rugosity. Lying by the sides of these processes were a num- 

 ber of small ribs, which seem to have been single-headed, inasmuch as no 

 double-headed ribs were found in the matrix. However, as Labidosaurus 

 lias quite this form of diapophyses posteriorly with double-headed ribs, 

 it is not impossible that such was the character of the ribs in this genus. 



The anterior border of the pedicel, beginning low down, projects for- 

 ward, so that if two vertebrae were closely applied the arch would rest 

 on two centra, though chiefly on the posterior one, and, so far as I can 

 determine from careful measurements, this would be the case with the 

 zygapophyses closely interlocked. 



That this was not the condition ordinarily, however, is rendered certain 

 by the presenot^ of extraordinarily large intercentra found in position 



