42 



ON DIPROTODOX MINOR, HUX. 



lobes separated by alongitudinal sulcus from mamillary tubercles 

 on the inner edsje, as we have them in Zygomaturus trilobus Macl, 

 also identified by Sir R. Owen with Nototherium mitchelli. 



As the only important difference between the teeth described 

 by Professor Huxley loses most of its significance in the presence of 

 an intermediate form, and as the probabilities of the case are against 

 the admission, without strong corroborative evidence, of a third 

 small Diprotodon, we are provisionally led to the conclusion that 

 there is but one, D. minor, Hux., and that this includes in its 

 synonymy D. (australis?) Hux. Nototherium mitchelli, part Ow — 

 Nototherium victorias, part Ow. 



Mandible — Confirmatory of the evidence given by the upper 

 jaw in favor of D. minor, we have the testimony of two mandibles 

 against the identity whereof the only thing that can be said is that 

 neither of them was found associated with a maxilla. Distinguish- 

 able in many respects from D. australis, they correspond with the 

 maxilla of 1). minor in the only feature in which they are comparable, 

 the length and relative breadth of the molar series d 4 — in 3 The 

 more perfect of these may be described. It is the left mandible of 

 a young adult whose age is registered in the narrow tract of dentine 

 on the hinder summit of the last molar. The rough labial tubero- 

 sity situated in I), australis below the premolar, is placed on the 

 diastema obliquely across the front fang of the premolar, and in 

 the vertical of tho hinder edge of the dental foramen. This orifice 

 is larger than in the larger species, opens on the middle of the jaw, 

 (below the middle in 1). australis), and is bounded posteriorly by a 

 convex vertical ridge descending upon the symphysial boss which 

 is much subdued, and presents a regular rotundity of form contrast- 

 ing with its expansive angularity in the mature I), australis. This 

 conspicuous feature of the D. minor symphysis is repeated in three 

 other examples. The outer surface of the incisive socket, so far as 

 preserved, does not slope inwards in front of the boss, but remains 

 parallel with the surface of the ramus betiind it. The surface here 

 is rendered concave by the prominence of the post-foraminal margin 

 in front ami the convexity of the bass below. The convexity of the 

 outer wall of the ramus commencing below the hind lobe of m 1 ; and 

 increasing to the root of the coronoid process, is higher and better 

 defined above and below than in the larger species, and gives off the 



