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RIENHAllDT ON 



In the facial part (" the beak"), the resemblance to the killers is, perhaps, somewhat less 

 striking ; for this part is shorter than the remaining part the skull, contrary to what is the case in 



those crania of killers which I have examined ; it is moreover very broad, and obtusely rounded in 

 front, and is also distinguished by tapering very slightly and very uniformly in a forward direction, 

 so that it is not much narrower even in the middle than in the place where it is broadest farther 

 behind, and these characters seem to become continually more distinct as the animal advances 

 in age ; at least we have found that the cranium of the Asnæs dolphin, evidently an extremely old 

 individual, was the one of the three having the shortest and broadest beak. One thing, how- 

 ever, produces a most conspicuous difference between our dolphin and the Orcas, we mean the 

 different breadth of the intermaxillaries ; for when we add the fissure between them filled with 

 the cartilage of the primordial vomer, then these bones occupy about two thirds of the whole 

 breadth of the beak in our crassidens, while in the Orcas they are much narrower than the 

 superior maxillaries. In this respect we find unquestionably a likeness with the ca'ing-whales, in 

 which the intermaxillaries, as is well known, are also, and even in a still higher degree, remarkable 

 for their breadth ; but beyond this no further resemblance is to be found with these in the struc- 

 ture of the beak. In the ca'ing-whales, far more than in our dolphins, the unusual size 

 of the intermaxillaries is produced at the expense of the superior maxillaries, and it is not 

 strange that the latter have a diminished share in the breadth of the beak, as the feeble set of 

 teeth of these animals only I'equires small and shallow sockets. Behind the short row of 

 teeth, the alveolar margin is further gradually twisted in such a way as to have an edge turned 

 outwards, and this exterior margin of the superior maxillaries is not placed on a level with the 

 intermaxillaries behind, but a little above them, by which means the surface of the beak be- 

 comes somewhat concave in this place. It is true that the intermaxillaries of Cuvier's Delphinus 



