MR. W. H. FLOWER ON THE OSTEOLOGY OF THE SPERM-WHALE. 567 
urged, and on far safer and more scientific grounds than the vague descriptions and 
partly imaginary drawings on which most of the earlier Physeteres and Catodontes were 
founded. Of these the most important is that set forth in the oft quoted memoir of 
Wall, where the detail with which the skeleton of the southern Cachalot is described 
and compared with what was known of the Cachalot inhabiting the northern seas, has 
succeeded in establishing, to the satisfaction of most zoologists, the species P. (Catodon) 
australis as distinct from P. (Catodon) macrocephalus. The diagnostic characters 
relied upon are as follows:—1. The entire head as compared with the body is rela- 
tively smaller. 2. The skull is shorter in proportion to its width and height. 3. The 
lower jaw is proportionately shorter. 4. The form of the sternum is different. It 
has been already shown that the first. three of these characters depend simply upon 
the immature condition of the specimen described. In the fourth the author has 
been misled by Beale’s description of the incorrectly articulated skeleton at Burton 
Constable, in which the body of the hyoid is appended to the hinder end of the 
sternum. Putting aside these supposed distinctive characters as valueless, there is not 
one other, presenting any approach to a specific distinction, pointed out throughout the 
memoir. Catodon australis, therefore, as founded and characterized in Wall’s work, can 
have no existence as a zoological species. 
It will be gathered. from the foregoing memoir that, although numerous discrepancies 
have been met with among various bones of the different skeletons examined, in some 
cases so marked that, if two individuals alone were known, they might easily have been 
considered specific, the comparison with a third example has nearly always proved a 
corrective to such a supposition,—and that, taken as a whole, the Yorkshire skeleton 
differs from the Caithness skeleton as much as the Tasmanian does from either. I am 
therefore quite unable, from the materials at present available, to point out any constant 
difference of specific. value between the Cachalot inhabiting the Australian seas and 
that occasionally visiting our northern coasts. 
It must not be inferred from this statement that I deny the possibility of their being 
specifically distinct. Similarity of osteological characters does not prove unity of 
species. Who would have suspected the specific distinction of the Lion and the Tiger, or 
the Quagga and the Zebra, if these animals were only known by two or three skeletons 
of each? But, at the same time, no new species should be admitted into the. system, 
unless its distinction is established either by well-marked and constant (1) anatomical 
characters, (2) external characters, (3) geographical distribution, or (4) peculiarity of. 
habit and mode of life. On no one of these points has it yet been shown satisfactorily 
that the southern and northern Cachalots differ, 
With reference to the geographical distribution, it may be remarked that, unlike the 
Right Whales, the Cachalots are essentially inhabitants of the tropical and warmer parts 
of the temperate seas, and that they pass freely from one hemisphere into another. 
Between the North Atlantic and the Australian seas there is no barrier interposed to 
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