THE COTYLOSAURIA 



141 



sauria Seeley (1892);' and Procolophonia Seeley (1889).^ The 

 question of immediate interest is, in which of these two latter groups? 

 if either, can Pariotichus and the other forms eliminated by Case 

 from the Cotylosauria be placed. Its interest has led me to re-examine 

 in the light of the recently accumulated facts concerning the older 

 reptiles, the excellent specimen in the Chicago University collections 

 described by Case some years ago^ as Pariotichus incisivus Cope. 

 For the general descrip- 

 tion of the specimen the 

 reader is referred to the 

 cited paper. By further 

 preparation of the speci- 

 men I am able to make 

 some additions of in- 

 terest. 



My determination of 

 the upper elements of the 

 skull (Fig. i) made inde- 

 pendently, agrees well 

 with Case's. On the un- 

 der surface, however 

 (Fig. 2), I am quite un- 

 able to differentiate the 

 pterygoids, palatines, and 

 vomers anteriorly, they 

 are so closely fused to- 

 gether. I do not feel at 

 all sure about the dis- 

 tinction of the parocci- 



FiG. I. — Skull of Lahidosaurus incisivus, upper 

 surface; one-half natural size. Pm, premaxilla; N, 

 nasal; M, maxilla; L, lachrymal; F, frontal; Pjr, 

 prefrontal; Pfr, postfrontal; Po, postorbital; /, 

 jugal; Pf, parietal foramen; P, parietal; Sq, 

 squamosal; Psq, prosquamosal; Qj, quadratojugal. 



pital as a separate element. The epiotics may be present, but I am 

 not sure. 



Eighteen presacral vertebrae were collected by Professor Case 

 with the specimen, and he was inclined to the belief that this was the 

 full number. Four of these, without rib attachments, are connected 



1 Philosophical Transactions, 1892, p. 106. 



2 Ibid., 1889, p. 270. 



3 Zoological Bulletin, Vol. II, 1899, p. 231 



