FOSSIL CARNIVORA. 



of Machaerodus were so long that he must have had some difficulty in opening his mouth sufficiently 

 wide to take in anything large, and thus it would seem that he actually overshot the limit of 

 perfection, and died of over-specialisation. The canines of the Sabre-toothed Tiger are, however, 

 not its only peculiarity : there is one less premolar on each side of the upper jaw than in the 

 modern members of the Cat family, so that the total number of teeth is reduced to twenty- eight,* 

 the smallest number found in any of the Carnivora. 



On descending to the rocks of Pliocene age, wo find, amongst many forms existing at the 

 present day, an animal called Gcdecynus, about the size of the Fox, and possessing many characters, in 

 its teeth, limbs, <fec., intermediate between those of the Dogs and those of the Civets. Another genus, 

 Hyainarctos, is almost exactly half-way between Dogs and Bears ; its molars have less of a cutting 

 character than a Dog's, and less of a grinding character than a Bear's, and its front premolars, though 

 much smaller than a Dog's, do not fall out altogether, as in the Bear. 



In the Pliocene, or Late Miocene strata, remains have been found of many existing genera, such 

 as Cats, Civets, Hyaenas, Dogs, Weasels, Ratels, and Otters ; but amongst these are several genera not 

 occurring in any of the more recent strata, and all, or nearly all, tending to bridge over the gaps which 

 separate existing families from one another. For instance, a perfect gradation between the Hyaenas and 

 Civets is afforded by two genera, Hycenictis and Ictitherium ; while Lutrictis shows affinities both with 

 Civets and Otters, Hemicyon with Dogs and Gluttons, and Dinictis with Cats and Weasels. 

 Another very interesting genus, Promephitis, belongs undoubtedly to the Weasel family, but is inter' 

 mediate between its three sub-families, the Weasels proper, Badgers, and Otters. Simoci/on, again, an 

 animal about the size of a Leopard, is described as having the canines of a Cat, the molars of a Dog, and 

 jaws shaped like those of a Bear. Lastly, Amphicyon is a large plantigrade animal, Bear-like for th~> 

 most part, but with trenchant molars, like a Dog's, and having a small additional or third molar on 

 each side of the lower jaw, the number of its teeth being thus brought up to that which may be called 

 the typical Mammalian number, namely, forty-four.f 



In the Eocene, or Lower Tertiary, still more remarkable forms occur, along with several genera 

 existing at the present day, such as the Cryptoprocta, Civet, Dog, and Marten, all of which are found 

 in the upper or more recent strata of the Eocene 

 formation. But lower down the genus Cyno- 

 don also connects Dogs with Civets ; and in 

 the very lowest beds occurs a large plantigrade 

 animal (Arctocyon), with a very small brain-case, 

 wide jugal arches, a complete set of forty-four 

 teeth, and altogether of a generalised character. 

 In the Eocene of North America, Limnocyon and 

 Prototomus occur low down, and in the Middle 

 Eocene a form as large as a Lion has been dis- 

 covered, to which the name Limnofelis has been 

 given, and also Orocyon, and some allies of the 

 Hycenodon. 



But we have not yet learned all that Palaeontology can teach us about the history of the Carnivora. 

 In the Eocene and Lower Miocene beds are found animals referred to the genera Hyccnodon, Pterodon, 



Palceonictis, and Proviverra, which, not content 

 with trespassing on the boundaries between existing 

 families, actually wander outside the Carnivorous 

 order altogether, and approach so nearly to the 

 Marsupials (Kangaroos, Opossums, &c.) that many 

 competent anatomists have proposed to plaee them 

 in the latter group. The premolars and molars 

 LOWER JAW OF HYJENODON. (After Gaudry.) in these extinct animals have sharp cusps, and 



SKULL OF AftCTOCYON. (After Gawlry.) 



* The dental formula is Incisors, 3 _ 3 canines, ^5 ', premolars, jug > molars, f^ = 28. 

 f The dental formula is Incisors, ,p^ j canines, j-j ', premolars, 4 _ 4 ', molars, 3^3 = 44. 



