302 The Am 





sauria which is nearly related to the Pelycosauria." The examination 

 of the sternal region in Pariotichus has led me to the conclusion that 

 the episternum and interclavicle are present and fused together in that 

 genus, and also to the belief that the episternum is present in the 

 genus Procolophon. The structure is generally similar in the two 

 genera, and I think that Seeley is in error in determining the element 

 in question in Procolophon as the interclavicle only.* Gegenbaur 

 pointed out in his Comparative Anatomy the different (i, e., membranous) 

 origin of the interclavicle of the Lacertilia, but he included it with the 

 episternum under the same name. The true episternum is not present 

 in the Lacertilia. It is present in the Sauropterygia and Testudinata 

 and probably in all the orders with one postorbital bar, or Synapto- 

 sauria, while it is wanting in most or all of the Archosaurian series 

 and in the Squaraata. Whether the element I have referred to in the 

 genus Naoaaurus as interclavicle, is that element or the episternum, 

 must remain uncertain until I can see it in place. Its edges are thin, 

 as in the interclavicle of the Lacertilia. Of course, the Reptilian 

 order which is in the line of ancestry in the Mammalian will have an 

 episternum and not an interclavicle only. The Stegocephalia among 

 Batrachia possess an episternum, with, perhaps, an adherent inter- 

 clavicular layer as in the Testudinata. 



Seeley describes four sacral vertebrae in Pariasaurus. In Empedias 

 there are but two. The pelvis is without obturator foramen. The 

 humerus has an entepicondylar foramen. The tarsal and carpal ele- 

 ments are incompletely known. 



There are palatine teeth in Empedias and Pariasaurus, but none in 

 Elginia ; vomerine teeth none. 



The inferior surface of the' cranium is known in Elginia, Pariasau- 

 rus, Empedias and Pariotichus, and has been described as to the first 

 three genera by Newton, Seeley, and myself. Pariotichus displays 

 generally s.milar characters. There is a pair of posterior nares and 

 a pair of zygomatic foramina, but no palatine foramen. The palatine 

 elements meet on the middle line, but gape behind. The vomers 

 (prepalatines) are distinct, and are well developed anterior to the pala- 

 ce ectopterygoid is large and has a prominent posterior border. 



'. have stated that i 



3 teeth on the vomer. Better 



preserved specimens of Pariotichus show that the teeth are reallv borne 

 on the edges of the palatines, which are appressed on the : 

 in the former genus. Similar palatine teeth are present in 1 ' 



; are wanting in Elginia. Teeth are also present on the posterior 

 r, 1889, p. 275, PI. IX, fig. 9. 



*Philos.Transac. '. 



