SYNOPSIS. 211 



Marsh, Fifth Annual Report of the U. S. Geological Survey (figure from the jireseni, 

 volume), fig. (37, p. 271, 1884. 



The snout in tlie type of this sj^ecies (number 1499) tapers in front, 

 where the nasals are divided by persistent sutures, and bear low rounded 

 tubercles. The nuixillary protuberances are connected by a low rounded 

 ridge. The upper surface of the skull behind these protuberances is 

 flattened, and, in the region of the fronto-nasal sutures, elevated. It is 

 separated from the lateral surface by a ridge, rising gradually upon the 

 parietal protuberances, which are connected by a transverse elevation 

 across the skull, above the brain case. 



The olfactory chambers were divided transversely by a bony septum 

 as shown in figure 32, page 30. 



The palato-maxillary foramen extends back nearly to the middle of 

 the second premolar. The premaxillaries are proportionally larger than 

 in Binoceras laticeps (number 1039), and straighter than in Dinoceras 

 niirahile (number 1036). They present pits, as if for rudimentary teeth, 

 as in number 1039. 



This species is based upon a s])ecimen (number 1499) collected in 

 June, 1874, by Mr. L. Lamotte, at Cattail Springs, Wyoming. 



The remains of this specimen consist of a skull, vertebme, etc. 



The geological horizon is in the 1 )inoceras l)eds of the Jliddle Eocene. 



The known remains of this species are preserved in tlie Museum of 

 Yale College. 



Tinoceras iiig:ens, Marsh. 



(Plates XV-XYIII, LVI.) 



Woodcuts: 9, j). 16; 17, p. 19; 23, p. 25; 28, p. 27; .t1, p. 45; 59, p. 55; 115, IIK, p. 105; 

 117, p. 1U8; 124, p. 119; 134, 1.S5, p. 136; 141, 142, p. 149. 



Marsh, Fifth Annual Report of the U. S. Geological Survey, (figures from the present 

 volume, viz:) figs. 46, p. 261; 52, p. 263; 58,"p. 267; 63, p. 269; 88, p. 281; 96, 97, p. 

 286; 126, 127, p. 297; 137, p. 302, 1884. 



The type specimen (number 1041) of this species was collected by 

 Mr. S. Smith, near Haystack ]\Iountain, Wyoming, in May, 1X75. 



This specimen consists of a skull, in excellent preservation. 



The geological horizon of this species is in the Dinoceras beds of the 

 Middle Eocene. ^ 



The known remains of this species are in Yale College IMuseum. 



