414 PROP. OWEN ON AN ANOMODONT REPTILE FROM 



31. Description of Parts of the, Skeleton of an Anomodont Eeptile 

 (PLATYPODOSATjRTrs* ROEFSTTJs, Ow.) from the Trias of Graapp 

 Eeinet, S. Africa. By Prof. Owen, C.B., F.G.S., &c. (Read 

 April 28, 1880.) 



[Plates XVI. & XVII.] 



In a former paper f a dental character in a Triassic reptile was 

 indicated which is repeated in some implacental members of the 

 Mammalian class. I have also noticed a like correspondence in 

 the skeleton of another reptile from the same formation in South 

 Africa J. 



Pursuing the work of extricating from the matrix the Triassic 

 fossils since received from that continent, indications still more 

 interesting of such relationship have come to light, which I now 

 proceed to submit to the Geological Society. 



The evidence of the genus and species of extinct reptile above 

 named, forming the subject of the present paper, consists of a series 

 of seven thoracic vertebrae, with portions of ribs, a sternal bone, 

 scapula, and a right humerus, all cemented to a mass of dark 

 quartzose rock. A smaller mass included a femur with the pelvis ; 

 but the latter is still under the chisel. The parts exposed in the 

 first block are the left side of the vertebrse, the scapula, and the 

 whole of the anterior surface of the humerus, which bone remains 

 attached, somewhat behind its natural position, to the right side of 

 the present portion of thorax. 



Vertehrm. — Of each vertebra the centrum is subcompressed ; the 

 sides are slightly concave lengthwise between the thick convex 

 borders of their mutually articulating terminal surfaces ; these are 

 concave (PI. XYI. fig. 1, a, h), the hinder one (5) is the deeper ; the 

 extent of intervening part of centrum (c) is 5 lines. The external 

 smooth lateral surfaces slightly converge towards the narrow in- 

 ferior one (ib. fig. 2). The neurapophysial suture (ib. fig.l, n' n') is 

 unobliterated. 



The neurapophysis (ib.fig.3,w) ascends, slightly contracting antero- 

 posteriorly and inclining outwards to form a neural platform, from 

 the sides of which the usual di- and zygapophyses are developed ; 

 from the summit of the arch rises a neural spine, n s. To the dia-* 

 pophyses of two of these vertebrae the proximal portions of the ribs 

 (ib. fig. 3, pZ) are attached ; these are subcompressed and feebly 

 channelled along the side exposed. 



The following are dimensions of the above parts of the thorax: — 



* TrXaTvs, broad ; ttovs, foot ; cavpos, lizard. 



t " On Cynodraco major" Quart. Journ. G-eol. Soc. vol. xxxii. 1876, p. 960 ; 

 ' Descript. and Illustr. Catalogue of the Fossil Reptilia of S. Africa,' 4to, 1876, 

 p. 70. 



X ' Descriptive and Illustrated Catalogue,' p. 48. 



