THE AUSTRALIAN MUSEUM MAGAZINE. 



269 



Two views of the skull of the dog. In the 

 upper one, which is a view from the side, the 

 preniaxilla, which bears three teeth (although it 

 appears in the picture to have four) is marked 

 Jm. Just behind it is the maxilla (Ml, with the 

 rest of the teeth. The nasal bones are marked 

 N. Just in front of them is a dark line showing 

 the opening of the nostril. In the lower figure 

 jhe skull is looked at from above. The chief 

 point of interest is the position of the nostrils 

 ( 12) and of the nasal bones (4). 



[Upper figure from fViedersheim's Comparative 



Anatomy). 



[Lower fitiiire from Reynold's Vertebrate 



Skeleton). 



the Tasmanian Royal Commission of 

 Fisheries in 1882 a witness stated that 

 he had caught in the fishing beds at 

 one time a warm blooded animal with 

 teeth like a shark. This description 

 would apply jierfectly to these extinct 

 or supposedly extinct whales and to no 

 other animal. 



There are many respects in which 

 this whale shows a nearer approach to 

 the ancestral mammals than do the 

 toothed whales of the present day. 



I show here the skull of a dog and 

 that of a dolphin of the present time. 

 Notice that the upper jaw of the dog 

 on each side is formed of two bones, 

 the premaxilla and the maxilla. Each 

 of these contains teeth, the premaxilla 



bearing the three front teeth (incisors) 

 while inserted into the maxilla are the 

 remainder of the teeth which are di- 

 vided into different sets according to 

 their shape and function. 



In the dolphin the jaw is also formed 

 of the premaxilla (Px) and the maxilla 

 (Mx). The maxilla bears all the teeth, 

 the premaxilla having none and the 

 teeth are more numerous than in the 

 dog and of similar shape throughout. 

 They are made sim])ly for holding, not 

 for cutting. 



Let us see what are the conditions in 

 this region of the skull in the Tasmanian 

 fossil. The premaxilla and maxilla 

 are present but the former has three 

 teeth as in the dog, while the maxilla 



