Tliat ucims liii!^ so far only been louiid in tlic Moccnc I'ornuilKtn. 'llir lionc 

 is rather thin, and sufficiently curved to indicate a convex carapace of moder- 

 ate thickness. The surface is marked with (^osely-packed shallow pits w itli- 

 ont material variation of l()rm on the proximal half of the hone. The result 

 is an ()i)Solete sculpture (piite similar to that seen in some species of the 

 genus to which it is at present referred. 



MeaniDyiiunts. 



M. 



Width of the lu.stal Ijoiic (». 02:50 



Tliickiios.s of tlic costal Iioiic 0. (!(K!;{ 



Niiiiilicr of ])it» ill l)'".0U1, (1. 



Lignite Cretaceous of Colorado; also, several fragments from Long 

 Lake, " Nebraska,' from Dr. H.iyden. 



?Plastomenus in.signis, xp. nor. 



Represented hy u portion of the right hyposlernal l)one of a tortoise 

 about the size of the la.st species, and from the same locality. The specimen 

 resembles, in its sculjjture, such species as the Plasfomenus trioni/choides, and, 

 in structural character, the species ol' Anosiira, but it is scarcely probable that 

 it belongs to either genus. It is flat, and has a narrowed, straight, inguinal 

 margin, at right angles to the fine suture with the hyosternal. The suture 

 with tlu! p()stal)domiiuil is partially goniphosial. Surface dense, polished, 

 marked externally with a reticulate sculpture of narrow ridges separating 

 larger and smaller areas wider than themselves. Inguinal edge thinner. 



Measurcmentx. 



M. 



Length of the hyposternal fore and .ift . 0. 02."> 



Thitkucss of the hyposterual at frout 0. 004 



Pits in 0™.010, six. 



Lignite Cretaceous of Colorado. 



TKIONYX, Geoffr 



Although species of this genus occur in the greeiisand of Cretaceous No. 

 4, in New Jer.sey, none have l)een discovered in the West below the horizon 

 of No. 6, or the Fort Union fresh-water beds. Dr. Leidy has described a 7'. 

 foveatus from the bad lands of the Judith River, Montana; and 1 have a<ltled 

 the foHowing: 



