0. C. Marsh—Structure of Mosasauroid Reptiles. 461 
The eg specimen of the present species was discovered last 
summer by Mr. G. G. Lobdell, Jr., and vertebree of a second 
individual by Mr. J. F. Quigley, of the Yale party, in the same 
formation, in Kansas, as the fossils already described. 
The additional species, previously described from the West, 
that can now be referred with certainty to the genus Lestosau- 
rus, are as follows :—Lestosaurus curtirostris, = L[iodon curtiros- 
tris Cope, Lestosaurus ictericus, = Holcodus ictericus Cope, an 
Lestosaurus corypheus, = Holcodus corypheus Cope. ; 
Rhinosaurus,* gen. nov. 
United premaxillaries large, forming anteriorly an elongated 
cylindrical muzzle, that projects some distance in front of the 
teeth ; posteriorly they contract gradually, and coalesce with a 
broad nasalelement. Mandibles closely in contact at distal ends, 
and projecting beyond the dental series. Parietal foramen of 
moderate si eeth stout, and more or less compressed an 
faceted. Palatines narrow, with bases of teeth unequally ex- 
posed. Quadrate small, with short posterior hook. Humerus 
small and slender. Manus and pes of nearly equal size. Cau 
dal extremity comparatively short, with articulated chevrons. 
Fhinosaurus micromus, sp. NOY. 
The present species is established on the greater portion of 
one skeleton, in good preservation, and fragmentary remains of 
several others. In the former skeleton, the skull is nearly en- 
tire, and shows well the more important characters of the genus. 
€ muzzle is much produced (Plate x11, fig. 2), and has a 
rounded obtuse extremity. The premaxillary suture is elon- 
continued as a ridge to the antero-internal ang 
end. The meatal pit is large, sigmoid in outline, and oblique 
* From jis, nose, and caipog, lizard. 
a 
