204 



DINOCERATA. 



Tinoceras affiiie, Marsh, '}>. s. 



Woodcuts: 16, 1). 10; and 178, 179, Ijelow. 



Figure ITS. — Vertical eection through cranium of Jinoceras affme. Marsli (No. 1074). 

 Figure 110. — The same specimen ; seen from above. 



ps. parietal supra-occipital sutme; /])■ fronto-parietal suture; o. ocei|)it:il cduilyle: o?. olfactory lobes of 



brain ; p'. parietal protuberance ; s. supra-occipital crest. 



Both figures are one-eighth natural size. 



In the type of this species (number 1574), the snout tapers, and the 

 nasals are divided by a. distinct median suture. 



The nasals are well preserved, and much resemble those of number 1041, 

 but are more perfect. As in number 1040, they are thoroughly co-ossified 

 to the extreme point, which is directed obliquely downward. The nasal 

 protuberances are placed obliquely, and are flattened on their outer 

 anterior surface. They are directed outward and upward, and are elongate- 

 oval in section, the long axes of the ovals making about a right angle with 

 each other in front of the snout. 



The maxillary protuberances are elevated, but of moderate size, and 

 are connected across by a rounded ridge. The parietal protuberances 

 present a moderately sharp ridge on their anterior faces, and are somewhat 

 club-shaped. They were connected across the top of the skull by a 

 rounded ridge. 



The foramen magnum is transversely oval, and rises nearly to the 

 same height as the occipital condyles. The post-glenoid ])rocess is robust. 



The occipital crest bears a rather ])rominent, but rounded, ridge along 

 the median line, above the foramen magnum. 



The palate is moderately excavated in front, and the palato-maxillary 

 foramen is opposite the first premolar. The diastema is thick, strong, 

 short, and straight. The vomer is ])reserved in this specimen, firmly 

 lodged in a groove in the upper surface of the maxillaries 



