114 PROCEEDINGS OF THE ACADEMY OP 



territories. The specimen consists of tlie greater portion of the 

 lower jaw of a pachyderm from the Bridger tertiary formation, 

 probably eocene, of AVyoming. It was discovered by Dr. J. Van 

 A. Carter, of Fort Bridger, in the vicinity of that place. In the 

 same localit}^ were also found remains of PalseosyojJS paludosus^ 

 and the curious turtle Anosteira ornata. 



The jaw belonged to an old individual, as indicated by the 

 worn condition of the molar teeth ; and the animal to which it 

 pertained was about the size of the larger Peccary. The jaw, 

 howevei", is of much more robust character than in the latter. 

 The two rami are completel^^ coossified at the symphysis, as in 

 recent pach^'derms. The chin, or forepart of the jaw, resembles 

 in its broad slope the corresponding part in the Rhinoceros or 

 Peccary, but is convergent as in the Beaver or other rodent. 



The forepart of the jaw is occupied by two large teeth, the 

 features of which are such that at first glance one would think we 

 had before us a portion of the skeleton of some huge representative 

 of the order of Rodentia. The two teeth curve upward and for- 

 ward in the same manner as in the latter, but are separated by a 

 decided interval, which at the edge exhibits alveoli for a pair of 

 small incisors. Hence the number of incisors appears to be four, 

 and the large teeth are to be regarded as the lateral pair. These 

 do not extend backward in their alveoli further than the position 

 of the premolars, and in this respect differ widely from the condi- 

 tion of the Beaver and other rodents. 



The form and construction of the incisors are wonderfully like in 

 the latter animals. As in these, their forepart alone is invested with 

 enamel, which is quite thick. They are, however, decidedly convex 

 in front, and not nearly' flat, as usual in rodents. They have been 

 worn oft' in a sloping manner, not only as in these, but also later- 

 ally, so that it would appear the corresponding upper teeth were 

 more divergent than the lower ones, or held a position related 

 Avith one another resembling the condition in the peccaries and 

 hogs, rather than in the rodents. 



Unless the laroe teeth described are to be res^arded as canines, 

 instead of incisors, thej' were absent, as in the Rhinoceros and 

 Mastodon. 



The fossil exhibits evidences of the existence of six molar teeth, 

 and there may have been a seventh in the series, but this is not 

 obvious in the specimen. The molars extended close to the posi- 

 tion of the large incisors, leaving no hiatus like that in Rhinoceros, 

 Mastodon, and the rodents, or like that in the Peccaries back of 

 the canines. 



Nearl}^ all the molars have been lost in the fossil, the imperfect 

 crown of the second true molar and part of that of the first alone 

 being preserved. The base of the crown of the last of the series 

 indicates a fore and aft three-lobed tooth, as in Palaeotsyops, 

 Titanotherium, and Palseotherium. 



The crown of the second molar is much worn, but in the entire 



[July 11, 



