CIIAP. xii.] DIFFERENT KINDS OF GATS. 431 



The living cats being thus uniform in structure, one alone stands 

 out as markedly distinct. This is the Cheetah with its imperfectly- 

 retractile claws and rudimentary cusp of the inner upper sectorial 

 tooth, its high skull, long limbs and tail, and long metacarpals and 

 metatarsals. In it also we saw that the first premolar may be 

 present or absent, but that the second premolar is greatly developed 

 vertically. Altogether this animal may, as has been said, rank as a 

 group or genus by itself, the genus Cyncelurus, of which genus the 

 above characters will form the definition. The Lynxes may also, as 

 we have seen, be grouped by themselves, but they can hardly be 

 reckoned as forming a distinct genus, although their special geo- 

 graphical range being almost entirely creatures of the north 

 temperate zone is a noteworthy character. 



All the other cats, however, must, without question, be included 

 in a single genus, Felis. 



It has been proposed to separate off, as a distinct genus, the cats 

 with a vertical pupil and an orbit closed behind by bone, and to 

 divide the round-pupilled cats into two genera according to the 

 presence or absence of a first upper premolar. But these characters 

 are too inconstant to serve such a purpose. We have seen that 

 in the lion, even the upper true molar may not only be wanting, 

 but the skull may show no trace of the tooth's past existence. 

 But though the genus Felis must be thus extensive, the kinds con- 

 tained within it may, for convenience, be considered as forming 

 certain sets, distinguished by trivial marks. Thus the male lion, as 

 normally developed, is distinguished from all other cats by its large 

 mane, and the tiger by its vertical stripes and large size. A few, 

 as the puma, jaguarondi, eyra, F. aurata, F. planiceps, F. badia, 

 and F. rutila, are separable from the rest by their uniform colour, 

 but the great bulk of the cats are black-spotted animals. A few 

 also may be distinguished from the rest as rather "clouded'' than 

 " spotted." Such are the F. marmorata, F. macrocclis, F. megalotis, 

 F. pajeros, F. caligata y F. Manul, F. neglecta, F. torquata, and 

 F. catus. Almost every transition, however, exists between the 

 spotted and the clouded cats, and some spotted forms occasionally 

 have their spots very slightly marked, so that generic distinctions 

 reposing on any such characters would be most futile. 



Fifty species of living cats have been here enumerated as probably 

 distinct, but it may turn out that certain of these are mere varieties, 

 while some forms here deemed varieties may possibly prove to be 

 really distinct species. It is the South American spotted cats ocelots 

 and margays which are specially difficult thus to determine, and with 

 regard to the smaller cats of China, and the adjacent parts of Asia, 

 a similar, though perhaps less degree of difficulty occurs. It may 

 be that F. Wagati, F. javanensis, F. microtis, and F. Jerdoni, will 

 have to be merged in other species. Nevertheless it may be con- 

 sidered certain that upwards of forty well-marked species of cats 

 now exist. 



14. A much larger number of species have probably existed in 



