ORDER CARNIVORA. 



1 42 1 



species in the Pleistocene of Europe; while the allied Plesisper- 

 mophilus has been described from the Quercy Phosphorites. 

 Among the Squirrels, of which the living genera have compressed 

 incisors, Sciunis itself ranges down to the Quercy Phosphorites in 

 Europe, and in North America occurs in the White River Mio- 

 cene ; the common existing 6". vul- 

 garis being found in the Norfolk 

 Forest-bed. The recent northern 

 genus Tamias occurs in the Pleis- 

 tocene of Europe and Nebraska ; 

 while Pseudosciurus and Sciuroides 

 are allied extinct genera from the 

 Upper Eocene of the Continent, in 

 both of which the molars are more 

 elongated than in Sciurus. Gym- 



1 3 



?wptychus i with JPm. 



Fig. 1299. — Palatal view of the right 

 upper and lower dentition of the Marmot 

 {Arctomys marmotta). Recent and Pleis- 

 tocene, Europe. The two teeth on the right 

 side of the upper figure are the premolars. 



M. -, from 



3 



the Miocene of North America, 



has more complex molars, and 



thereby approaches Pteromys ; while Meniscomys (with which Alio- 



2 

 mys is apparently identical), with Pm. -, from the same deposits, 



presents some resemblances to the American Haplodontidce (which, 

 like the Anomaluridce, are unknown in a fossil state), Sciurodon 

 from the Quercy Phosphorites is regarded as a closely allied 

 genus. 



Finally, we may here mention the small Decticadapis, of the 

 Lower Eocene of Rheims, which appears to be a Rodent, although 

 its affinities cannot yet be determined. 



Order VIII. Carnivora. — Although the existing Carnivora can 

 be denned with fair exactness, yet the fossil forms here included in 

 this order render such definition almost or quite impossible. All 

 the known forms are, however, unguiculate, with never less than 

 four digits to each foot, all of which bear claws ; and the pollex and 

 hallux are never opposable. The dentition is diphyodont and 

 heterodont, and (with the exception of the canines of the Trichechidce) 

 the teeth have closed pulp-cavities. The incisors are very generally 

 three in number, the third being the largest ; the canines are strong, 

 pointed, recurved, and larger than the incisors ; while the first pair of 

 incisors never have an interval between them. The cheek-teeth vary, 

 but are usually compressed in the anterior part of the series ; while if 

 the molars are tuberculate, they are not complex and divided into 

 lobes by deep infolds of enamel. The condyle of the mandible 

 forms a transversely elongated half-cylinder, working in a deep 

 glenoid fossa, protected by a large postglenoid process. The 



