354 PEOPESSOE OWEN ON THE SPECIES OP PHASCOLOMYS. 



verse convexity is less so, and this part of the symphysis is rather longer and narrower 

 than in the other two mandibles. In these respects the third mandible approaches 

 nearer to Ph. latifrons. But it differs, as do the other mandibles of the same species, 

 as well as those of Fh. vomhatus (ib. fig. 2, 1, s), in the larger, especially broader incisive 

 alveoli, and the oblique course of their upper margins from the mid line of the sym- 

 physis outward and backward. The fore end of the symphysis of Ph. latifrons is at 

 once recognizable by the narrower outlets of the incisive alveoli, and the more trans- 

 verse course of their upper border (PI. LVII. fig. 3). The lateral borders of the outlets 

 are also more nearly vertical (PI. LIV. fig. 3, s*), and do not slope backward as they 

 descend, like those of the incisor alveolar outlets in Ph. platyrhiims (ib. fig. 2) and Ph. 

 vombatiis (ib. fig. 1)'. 



With the narrower alveoli associated with the more compressed form of the incisors 

 of Ph. latifrons one may predicate a generally narrower diastemal part of the sym- 

 physis, the upper surface of which, with a median canal towards the end and the two 

 parallel longitudinal grooves obsolete or nearly so, is better defined from the sides of 

 this part of the symphysis (PI. LVII. fig. 3, I, s'). In one jaw of Ph. latifrons the 

 defining ridges are sharp, and the intervening upper surface is concave transversely to 

 near the incisive outlets, where the defining ridges subside. I may note that the ante- 

 rior outlet (y) of the dental canal, in three mandibles of Ph. platyrhinus (PI. LIV. fig. 2), 

 is 1 inch 4 lines, or 1 inch 5 lines, behind the foremost point of the symphysis. In 

 one mandible of Ph. latifrons (ib. fig. 3) it is 1 inch behind the fore end of the sym- 

 physis; in another mandible it is 10 lines from the same part. The foramen is more 

 anteriorly situated in the broad-fronted or hairy-nosed species ^ I may further note 

 that, in the mandibles of two individuals, examined since describing that of the type 

 skull of Ph. latifrons, the intercommunicating foramen from the entry of the dental 

 canal to the outer surface of the base of the coronoid is smaller in one (PI. LV. fig. 4, p), 

 as in the type mandible, than in the platyrhine and Tasmanian Wombats; while in 

 another mandible of Ph. latifrons it did not exist. It is interesting to find this variety, 

 because, in the great Diprotodon and Notothere, with some afliinities to Phascolomys, the 

 absence of the perforation of the base of the coronoid process is the rule, as in the 

 Marsupialia generally, and this supports Dr. Murie's view of the hau-y-nosed Wombat. 



The mandible of the Tasmanian Wombat has the singular proportions of being as 

 broad as it is long. In the specimen figured (PI. LIV. fig. 1) the length is 4 iuches 

 6 lines. In one jaw of Ph. platyrhinus the length is 6 inches, the breadth 5 inches 



' This latter character, differentiating Phascolomys vomhatits from Ph. latifrons, is shown in figs. 3, c & 7 c of 

 pi. xxxvii. torn. cit. 



■ This character is shown in the figures of the mandible of the Tasmanian and continental broad-fronted 

 Wombats in pi. xxxvii. of my " Second Memoir" (torn. cit.). But I could not then, as now, depend upon the 

 constancy of such character, in which the platyrhine continental Wombat, as usual, resembles the Tasmanian 

 species. 



