NO. 1870. 



NEW M0SA8AUR0ID REPTILE—GILMORE. 



481 



The other germ teeth, as well as the comparative size of the 

 cavities, show that the teeth increase in size from front to back, 

 the more anterior being somewhat elongated with subacute apices. 

 The second germ tooth is elliptical in cross section. 



The mature teeth contain in the interior a large conical pulp cavity, 

 as shown by the broken base of the eighth tooth (see pi. 40). 



Leidy/ in describing some isolated mosasaurian teeth, says: ''They 

 are generally divided in front and behind by an acute ridge into an 

 inner and outer surface. In some teeth, apparently belonging to the 

 most posterior dental series of the jaws, and to those of the pterygoid 

 bones, there is only one ridge, which is situated along the back or 

 concave border of the crowns." It is of interest to note a similar 

 condition of the carinas in the teeth described here. 



It is in the peculiar type of dentition that this animal may be best 

 distinguished from the other mosasaurians, and that these teeth indi- 

 cate a food habit different from that usually attributed to members 

 of this group is very evident. 



Regarding the character of the food upon which the mosasaurs 

 subsisted, Dr. S. W. Williston expresses the opinion that it "con- 

 sisted almost exclusively of fishes, living or dead, and such small 

 animals as drifted upon the water,"" These observations are based 

 upon those animals having the sharp, recurved teeth of the usual 

 mosasaurian type. The teeth of Glohidens, however, indicate dif- 

 ferent food habits. 



The posterior teeth of this form were undoubtedly used only as 

 crushing instruments, and being marine animals it is quite reason- 

 able to suppose their food consisted of shell fish, crustaceans, etc., 

 the harder portions of which were crushed between the bulbous 

 teeth before being swallowed. The two functional teeth remaining 

 intact show wear only on the very top. 



Measurements. 

 The sockets for 9 teeth occupy a distance on the maxilla of. 



tnin. 

 210 



Frontal. — The frontal bone is broad and heavy with the usual tri- 

 angular shape. In its massiveness it resembles those of Platycarpus 

 and Brack]] saurus, more particularly the latter. 



1 Smiths. Contr. Knowl., vol. 14, 1865, p. 49. 



2 Univ. Geol. Surv. Kansas, vol. 4, 1898, p. 214. 



94428°— Proc.N.M. vol.41— 11 31 



