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 Arctocyonide, and the other by the likewise 
extinct family Hyenodontide. 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 Subursidz 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 
Machzrodus 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 #luroidea containing the families Viverride or 
civet cats, Hyenide or hyzenas, Cryptoproctide including the 
Foussa of Madagascar, and Felide, the cats. 
II. Sub-order Arctoidea embracing the families Urside or 
bears, and Mustelide or martins. 
III. Sub-order Cynoidea embracing the Canide or dog 
family. 
Susorper AVTLUROIDEA. 
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 bullze inflated, 
