MAMMALIA. ' 29 



Epomophorus, Bennett. — Tail none. Neck with a tuft of hair on each side. 

 Lower joint of thumb very long, webbed. E. Whitii, E. Gambianus. 



Eleutherura, Gray. — Tail short, free, in a nick on the middle of a narrow 



interfemoral membrane. Lower joint of the thumb ? Neck without any 



glands on sides. E. Hottentotta. 



Xantharpyia, Gray. — Tail with the base inclosed in the underside of the 

 interfemoral membrane. Neck without any glands. Lower joint of thumb rather 

 elongate. 



III. Wings from the side of the back. Head short, swollen. Nostrils 

 tubular. Grinders 4-5. 



Cynopterus, F. Cuv. (Pachysoma, J. Geoff.) — Tail short, inclosed in the 

 interfemoral membrane. Lower joint of thumb elongate. Wings attached nearly 

 to the base of the toe. 



MeGjEra, Temm. — Tail none. Lower joint of thumb very short. Wings 

 attached nearly to the base of the toe. 



IV. Wings from the middle of the back. Head short, swollen. Nostrils 

 tubular. Index finger clawed. 



Harpyia, Jlliger. — Tail elongate, free at the end. Lower joint of the thumb 

 elongate. Wings attached nearly to the middle of the outer toe. H. Pallasii. 



V. Wings from the middle of the back. Index finger not clawed. Head 

 elongate, conical. 



Cephalotes, Geoff. — Tail inclosed at the base. Interfemoral membranes 

 with a diverging muscular band on each side to the thighs. Lower joint of the 

 thumb elongate, as long as the upper. 



The latter genus has much the general characters of Pteropus, and would 

 thus appear to unite together the two extremities of the series. 



The relative proportion of the two joints of which the thumb of the wing is 

 composed, affords a very good character for the determination of the genera 

 among the Noctilionine and Pteropine Bats. The lower joint being always 

 affixed to the wing by a web which reaches to a little above the base of the 

 upper joint, so that it, at the same time, indicates the width of the membrane 

 on the front edge of the wing. It is the more necessary to make this remark, 

 as M. Temminck, who appears to pay so much attention to the osteological char- 

 acters of genera and species of bats, erroneously remarks : " Chez les Cheiroptbres 

 Insectivoresln, pouce des ailes est toujours tres court, compose d'une seule articula- 

 tion et de l'ongle avec sa phalange." — Monog. ii. 51. In this difficult group, any 

 character that will assist in separating the species into small groups is of con- 

 sequence. 



