257 



PliOTOSTEGA TOREUOSA, Copc. 



Proceedings of llio Aiiicricau Philosophical Society, li-T'J, lin (wlieio Platicnrptis is written 

 {lapsH calami); iiiul Ilayilon's Annual Report ol' the United States Ocolof;ical Survey, 

 1872, 330, 3:!4. — Atlantochchjs tiihcro.us, Lcidy, Report to the United States Geological 

 Survey oftlie Territories, 4t(), vol. 1, 1873, p. 312. 



Cretaceous of Mississippi. 

 Proto.stega neptunia, Cope. 



Proceedings of the American Philosophical Society, 1872, p. •V.V.i.—Allantochdys vtorloiiii, 

 Leidy, Report of the United States Geological Survey of Iho Territories, I, 1873, p. 

 342; Moaanauius mitchiUi, h^•Ady (pars), Cretaceous Reptiles of tlie United States, 

 18U5, p. 43, 110, Plate VIII, tigs. 3-4. 



Greeiisaml, No. *?, of" New Jersey. 



LYTOLOMA, Cope. 



Extinct IJatr.uliia and Reptilia of North America, 187(1, p. 144. 



Lytoloma jeajcesit, Cope. 



L. c, p. 145. 



Grecnsand of No. 5, New Jersey. 

 Lytoloma angusta, Cope. 



L. e.,p. 145; Chelonv sopita (part), Leidy, Cretaceous Reptiles of the United States,]). 105, 

 Plate XIX, fig. 2. 



Grceiisaud of No. 5, New Jersey. 



OSTEOPYGIS, Cope. 



Proceedings of the Academy of Philadelphia, 180.-J,p. 147 ; E.xtinet Batraehia and Reptilia of 

 North America, 1870, p. 132. 



In this genus, the alveolar surfaces are horizontal, very wide, and entirely 

 ilat. Tlie alveolar edge is not generally reflexed, even at the broadly-rounded 

 apex, but is acute. As already described, there are eleven marginal bones, 

 which, with the pygal, make twenty-three in all. The first and last are 

 witliout corresponding costal bone, so that the number of the latter is nine. 

 I formerly suspected that the eleventh marginal of the O. sopitus is connected 

 with a special costal, the entire number in this species being tints ten ; but 

 subsequent investigation does not establish the view, though it is not j'ct dis- 

 provcn. For the present, therefore, I place this species in Osteopygis. I now 

 add another species to the genus, making the entire nunil)er lour; and (he 

 following tabic points out the distinctive characters: 

 .•J3 c 



