No. I.] ARRANGEMENT OF THE SAUROPSIDA. 103 



The same I should like to say in regard to the Reptilia. I can- 

 not see how the Testudinata, Lacertilia, Nothosauridae, etc., 

 with the ectcpicondylar foramen in the humerus, could be devel- 

 oped from the Theromorpha with the entepicondylar foramen. 

 It is true we know some Permian Reptiles which possess both 

 the canals ^ in the same way as Sphenodon ; but whether these 

 forms are Theromorpha or Rhynchocephalia is a question. 



I think it is very much more probable that the Theromorpha 

 and Rhynchocephalia had a common reptilian ancestor below 

 the Permian in the Carboniferous. 



Cope^ has described a fossil from the Carboniferous of Brazil, 

 which he considers as Batrachian, with query. I have shown 

 that it is probably a Reptile^ allied to the Rhynchocephalia. 



This fossil, which Professor Cope calls Stereo sternum tumi- 

 dum, has notochordal vertebrae, and the humerus with an 

 epicondylar foramen ; but the principal character of this animal 

 consists in the presence of five distinct tarsal bones in the 

 second row. This seems to me of very high importance. No 

 Reptile, living or extinct, has more than four tarsal bones in the 

 second row ; the fourth and fifth digit is always supported by a 

 single bone, — single even in the embryo. The Rynchocephalia, 

 the Protorosauria, the Pelycosauria, all have only four tarsal 

 bones in the second row. 



This one character, if it is true, seems to be strong enough 

 to allow the formation of a new order of Reptiles, which con- 

 tains Stereosternum ; for this order I propose the name Pro- 

 ganosauria. 



But can we consider the Proganosauria as the ancestors of the 

 other Reptiles? Possibly we may if we take the Proganosauria 

 in a general sense. Stereosterum itself is certainly not on the 

 direct line ; it is a specialized member of the Proganosauria, like 

 Echidna^ a specialized member of the Prototheria (Monotre- 

 mata). In some later time I hope to give more detailed commu- 

 nications on the philogeny of the single groups of Sauropsida. 



New Haven, Conn., Sept. 26, 1886. 



^ H. V. Meyer. Reptilian aus dem Kupfersandstein des West Uralischen Gouverne- 

 ments Orenburg. Palaeontographica, Bd. 15, Cassel, 1865-68, pp. 97-130. 



* Cope, E. D. A Contribution to the Vertebrate Paleontology of Brazil. (Read 

 before the American Phil. Soc, Apr. 17, 1885.) Pal. Bull., No. 40. 



^ Baur, G. Die zwei Centralia im Carpus von Sphenodon . . . Zool. Anz., 

 No. 219. 18S6. 



