172 J. B. Hatcher — Recent and Fossil Tapirs. 



scarcity of nourishment. The more molariform superior pre- 

 molars and the usually larger size and more robust character of 

 all the teeth of G. dakotensis at once distinguish it from 

 O. occidentalis. Several specimens in the Princ. Coll. are 

 referred to this species, one of which (No. 11159) consists of a 

 median ungual phalanx, found associated with a fragmentary 

 lower-jaw, in which the inferior dentition, excepting the canine 

 and m. 3, is complete and in a splendid state of preservation. 

 The ungual phalanx and a crown view of the teeth are shown 

 in figs. 3 and 3a, plate III. This specimen was found by Mr. 

 Wells, and no record was kept as to the horizon ; from the 

 nature of the matrix it appears to be from the Oreodon beds 

 below the Metamynodon layer. There may be some doubt as 

 to whether the ungual found associated with the teeth really 

 belongs with them, but from the texture of the bone, color, 

 etc., I believe they pertain to the same individual ; it is in 

 shape remarkably like the same bone in Mesohippus, but much 

 larger than that in any species of that genus known from the 

 lower Oreodon beds. It also resembles the same bone in the 

 third digit of Elasmognathus and like that bone in this genus 

 and in Mesohippus it is notched in front. 



The incisors in the present specimen are very large, chisel 

 shaped and their crowns are slightly excavated or cupped. 

 The premolars and molars are very strong. 



Measurements of C. dakotensis (JVo. 11159 Princ. Coll.) 



Length of inf. pms. and ms. 1 and 2 75 mm 



" " ..40 



Depth of ramus below ra. 1 35 



Length of ungual phalanx . _ 24 



Breadth " " 22 



Recent Tapirs. 



I do not expect to be able to add much to our present knowl- 

 edge of recent Tapirs, but rather to collect and condense a 

 part of what is already known of the dental characters, and 

 the osteology of the skull, in the five now generally accepted 

 species ; with a list of the synonymy of each, complete, in so 

 far as the literature available will permit. The following key 

 to genera and species is submitted. 



A. Maxillaries greatly expanded superiorly and embracing the 

 mesethmoid cartilage, which in adult specimens is ossified and 

 extends as a bony plate far in front of the nasals. Premaxillaries 

 short and obtuse posteriorly _ Elasmognathus. 



