﻿MULTITUBERCULATA. •»83 



approximate size of a Rabbit. A smaller species, of which an 

 upper molar tooth is represented in the figure on page 281, has 

 been obtained from the Triassic rocks near Strasbourg. 



FAMILY BOLODONTID.E. 

 GENUS BOLODON. 

 Bolodon^ Owen, British Mesozoic Mamm., p. 6 (187 1); Lydek- 

 ker. Cat. Foss. Mamm. Brit. Mus., pt. v., p. 203 (1887). 



Nearly allied to the preceding family is a second one, typically 

 represented by the genus Bolodon, first described from the 

 upper Jurassic Purbeck rocks of Dorsetshire, but apparently 

 also occurring in the corresponding beds of the United States, 

 where, however, it has received a distinct name. 



In this family the four upper molars are longer than broad, 

 and each carry only two longitudinal ridges, separated by a 

 deep median groove, and each bearing several blunt tubercles. 

 The upper premolars have triangular crowns, surmounted by 

 three tubercles. 



Minute molar teeth very similar to those of Bolodon from the 

 Triassic rocks of Stuttgart and Somersetshire, described by the 

 name of Microlestes^ are perhaps referable to the present family, 

 although in the absence of any knowledge as to the nature 

 of the premolars, it is by no means certain that the genus 

 should not rather be assigned to the undermentioned Plagiau- 

 lacidce, 



FAMILY POLYMASTODONTID^. 

 GENUS POLYMASTODON. 

 FoIy7?iastodon, Cope, American Naturalist, vol. xvi., p. 684 

 (1882); Lydekker, Cat. Foss. Mamm. Brit. Mus., pt. v., 

 p. 200 (1887). 



The lower Eocene rocks of New Mexico have yielded the 



