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described one caught, latitude seventy-seven degrees north, 

 as having fifty-two teeth. Anderson, in 1746, described one 

 with fifty teeth ; and two others afterwards with forty-two 

 and fifty-one respectively. In 1770, E-obertson described one 

 cast ashore at Leith, with forty-six teeth. But such early 

 naturalists were not very accurate observers of specific dis- 

 tinctions, and it is even supposed that more than one of them 

 may have taken other Cetacea, particularly the genus Hyperoo- 

 don, for true CatodontidcB, or sperm whales. However this may 

 have been, Beale positively describes the Yorkshire sperm 

 whale as having in the lower jaw forty-eight teeth, twenty- 

 four on each side. Cuvier does not mention the number he 

 found in his Audierne specimen, but on examining his figures 

 we see that a supposed young cachalot, of which the under 

 iaw is preserved in the Parisian Cabinet d' Anatomic Comparee, 

 has twenty on each side. Cuvier himself, however, is inclined 

 to think that this last jaw may have belonged to an adult 

 animal distinct from the sperm whale, and he says that his 

 London specimen of true cachalot — his typical Physeter macro- 

 cephalus — has fifty-four teeth in the under jaw. Our Sydney 

 specimen has only forty-two teeth, so that although we may, 

 with the celebrated John Hunter, imagine it very possible 

 that sperm whales, according to age and other circumstances, 

 vary in the number of their teeth, we need not preclude our- 

 selves from supposing that these remarkable difierences may 

 also in some degree have their origin in the species being 

 distinct. 



The Sydney Museum is in possession of two other 

 under jaws of Pacific Ocean sperm whales, besides the one 

 appertaining to the complete skeleton under examination. 

 One of these is fifteen feet long, and to be in proportion with 

 our whale, must have belonged to a skeleton sixty feet long, 

 or more, without the intervertebral cartilages. This under jaw, 

 as far as its dilapidated state will allow us to ascertain, had 

 only forty -two teeth, and must, by the following proportions, 

 have belonged to a species distinct both from Cuvier's London 

 and from the Yorkshire whales. The other under jaw has 



