60 BULLETIN NO. VII. 



According to the dentition, all living and fossil carnivorous 

 animals might be grouped under two types, the one represented 

 by the fossil family Arctocyonidce, and the other by the likewise 

 extinct family Hycenodontidce. The former have the characteris- 

 tic dentition of omnivorous animals and the latter of carnivo- 

 res. Both had 44 teeth while the latter had five premolars, 

 the last two of which were sectorial. 



The sectorial of the upper jaw is always one of the milk 

 teeth while that of the lower jaw belongs to the permanent 

 series . The variations from the original type which are ob- 

 served in modern carnivorous animals consist in reduction in 

 the number and various modifications in the form and use of 

 individual teeth. No living carnivore has more than the origi- 

 nal number, 44 . In the dogs and bears the number is reduced 

 to 42 while the Subursidaa have two less. The badgers have 

 36; in all these cases, however, the molars exhibit the true 

 omnivorous characters. 



The true carnivores, as represented typically by the cats, 

 have only 30 teeth. The animal in this order which possesses 

 the fewest teeth is the Patagonian Lyncodon which has 28, 

 i. e., one premolar less than the cats on either side. Among 

 the fossil cats is an instance of still greater reduction in the 

 Machaerodus with its monstrous walrus-like upper canines. 



Although, as above said, the dentition affords a basis for 

 sub -dividing the order into two groups it is found convenient 

 to form three sub-orders as follows: 



I. Sub-order ^Sluroidea containing the families Viverridce or 

 civet cats, Hycenidce or hyaenas, Cryptoproctidoe including the 

 Foussa of Madagascar, and Felidce, the cats. 



II. Sub -order Arctoidea embracing the families Ursidce or 

 bears, and Mustelidce or martins. 



III. Sub-order Cynoidea embracing the Canidce or dog 

 family. 



SUBORDER ^ELUROIDEA. 



The characters upon which this suborder is founded are 

 technical and the real basis for the subdivision is found in simi- 

 larities of structure and habits which connect the different 

 members of this group more closely with each other than with 

 members of the other suborders. The points usually selected 

 as distinctive are the following: Teeth without tuberculate 

 crowned molars, reduced in number. Auditory bullas inflated, 



