THE CHEIROPTERA, 387 



upon fruits. With the single exception of Hypoderma, all 

 the genera embraced in this group have a nail on the second 

 digit of the manus, and the crowns of the molar teeth, which 

 soon wear down, are, when entire, divided by a longitudinal 

 furrow. 



The incisors do not exceed ^j. 



The pyloric portion of the stomach is immensely elongated. 



The nose has no foliaceous appendages, and the well- 

 developed pinna of the ear has the ordinary form, neither the 

 tragus, nor any other part, being unusually developed. 



These Bats are confined to the hotter parts of the Old 

 World and of Australia, where, from their dog-like heads and 

 reddish color, they are known as " Flying-Foxes " (Pteropus, 

 Sarpy ia, etc.). 



b. The division of the Insectivora contains Bats which, for 

 the most part, live upon insects, though some delight in fruits, 

 and others suck the blood of larger animals. 



The second digit of the manus is devoid of a nail, and 

 sometimes is without an3' bony phalanges. 



The stomach is usually pyriform, with a moderate cardiac 

 enlargement. The molar teeth almost always have such a 

 pattern as is observed in the typical Insectivora, and do 

 not exceed six, or fall below four, on each side above and 

 below. 



The incisors are ordinarily |J-j or ?^, but their number may 

 be much reduced. 



The integument of the nose is developed into an append- 

 age which is sometimes very large and leaf-like, and the tragus 

 of the large ears is often similarly modified. The tail is often 

 long, and sometimes prehensile. 



The genera Desmodus and Diphylla (of which the group 

 Hbematophilma has been formed) are the most completely 

 blood-sucking of all the Bats in their habits. They have a 

 pair of enormous, sharp-pointed, upper incisors, while the four 

 lower incisors are small and pectinated. I'he canines are very 

 large and sharp, and the molars, which are reduced to two 

 above and three below, on each side, have their crowns con- 

 verted into sharp longitudinally disposed ridges, like the; 

 edges of scissors. In Desmodus, the very narrow oesophagus 

 leads into a stomach which would be of extremely small di- 

 mensions, were it not that its cardiac end is dilated into a 

 great sac, which is longer than the body, and lies, folded up 

 on itself, within the cavity of the abdomen. Into this sac it 



