CHAP. XII.] 



DIFFERENT KINDS OF CATS. 



439 



Of existing cats, it is the clouded tiger (F. macrocelis) which 

 most resembles Machcerodus, not only by its very long upper canines, 

 but also by the shape of its skull. Felis planiccps, with its large 

 upper premolar, shows a certain affinity towards fossil forms which 

 have more developed premolar teeth than have any of the exist- 

 ing cats. 



As to the fossil cats, in addition to the structural facts already 

 mentioned, it is important to note that Archalurus, Dinictis, 

 Nimraviis, Pogonodon, and Hoplophoneus agree in differing from all 

 existing cats (and from other fossil cats, so far as has been yet ascer- 

 tained) in that the carotid and condyloid foramina open separately 

 from the foramen lacerum posterius, and in that the ali-sphenoid 

 develops a lamina of bone to embrace the external carotid artery, 

 the aperture left for the artery forming what is called an all-sphenoid 

 canal* In these respects, however, Machcerodus smilodon resembles 

 existing cats. 



It is abundantly evident that the differences between any of the 

 species which now live are very small compared with those which 

 separate such forms as Archcelums and Eusmilus from existing 

 species or from one another. It is the two last-mentioned genera, 

 together with the sabre-toothed Macha3rodonts, which exhibit to us 

 the most extreme and divergent structures as yet discovered, amongst 

 those various widely spread, or long existing, forms of animal life 

 which can make a valid claim to be considered as belonging to the 

 great feline group to be, in fact, some amongst the various "kinds 

 of cats." 



* These facts are mentioned by Pro- 

 fessor Cope (see "American Naturalist," 

 December, 1880, pp. 834 and 835) in a 

 paper which has only reached my hands 

 as these pages are passing through the 

 press. On account of the differences in 

 the cranial foramina, Professor Cope 

 divides the cats into two families : 

 I. Felidse ; II. Nimravidse. But the 

 conditions in this respect presented by 

 Pseudcdurus and Eusmilus have not yet 

 been described. Moreover, while dis- 



posed to admit the claim of Arclicelurus 

 to rank as a distinct sub-family did it 

 stand alone, it seems to me that Dinictis, 

 Nimravus, Pogonodon, and Hoplophoneus 

 go far to bridge over the differences 

 between it and the other cats, and I 

 cannot regard the two last-named genera, 

 as deserving to be ranked in a sub-family 

 distinct from the bulk of the Felidae., 

 How exceptional is not Otocyon amongst 

 the Canidte ! 



