236 CASE. [Vol. II. 



between the orbit and the nostril larger and longer than the 

 others, and lying outside of the closed dentary bone. Mandib- 

 ular symphysis not sutural, but ligamentous. Terminal man- 

 dibular tooth not small. Teeth not faceted, simple." 



The species iticisivus was described in 1886 (5) (p. 291) : " The 

 muzzle is quite prominent, a character somewhat exaggerated 

 in the specimen by pressure. The nostrils are large, lateral in 

 direction, and situated close to the end of the muzzle. The 

 orbits are sub-round, of medium size, and look mainly upwards 

 in the present condition of the specimen. One of the most 

 important peculiarities of the species is the disproportionately 

 large size of the iirst or anterior incisor or premaxillary tooth. 

 The crown is conical and nearly straight, with an acute apex 

 slightly posterior to the central point. Its section at the base 

 is slightly angulate. The two other premaxillary teeth are much 

 smaller, the third quite minute and with a sharp apex. 



" There are three maxillary teeth separated by rather wide 

 interspaces, anterior to the large tooth, which give character to 

 the genus. The latter is abruptly large, but not equal in dimen- 

 sions to the large first incisor. Posterior to it the maxillary 

 teeth are closely placed, and with obtuse crowns. They com- 

 mence very small, and increase in size posteriorly. At a point 

 where the palatine or ectopterygoid, as the fact may be, joins 

 the maxillary, the tooth-bearing surface is wide, and supports 

 four rows of small, obtuse-crowned spaced teeth of equal size. 

 This dental patch is triangular, with its long angles extending 

 anteriorly and posteriorly. The latter angle terminates a little 

 posterior to the middle of the orbit. The teeth have a small 

 axial pulp cavity, and the dentine is perfectly simple. 



" The head sculpture is well defined, and is reticulated in 

 pattern." 



Additional Description of the Head. — On one side, in the 

 specimen here described, there are sixteen maxillary teeth 

 visible ; allowing for lost teeth, there were about nineteen in 

 the series ; this number is probably not constant for the 

 species. The enlarged maxillary tooth, which is only slightly 

 larger than the adjacent teeth, is the sixth from the anterior 

 end, probably the seventh of the complete series. Posterior 



