THE FAMILIES AND GENERA OF BATS. 177 



dontidse have been almost universally associated with the Phyllo- 

 stomidse. AA^inge placed Brachyphylla with them, but otherwise they 

 have been regarded as the only members of the group. 



Remarks. — The Desmodontidae are somewhat closely related to the 

 Phyllostomida', as shown by the structure of the palate, wing, and 

 shoulder girdle, but their modification for strictly sanguivorous 

 habits is so extreme that it seems quite unnatural to retain them in 

 the same family. It is hardly possible to suggest which group of 

 the Phyllostomes is likely to contain their nearest allies, though a 

 possible relationship with the Hemiderminse is suggested by the 

 noticeably trenchant molars of Rlunophylla. 



Principal subdivisions. — The members of this family represent 

 three genera. 



KEY TO THE GENEHA OF DESMODONTIDAE. 



Outer lower incisor seven-lobed ; lower cheek teeth four Diphylla, p. 170. 



Outer lower incisor with not more than two lobes ; cheek teeth three. 



Inner lower incisor deeply two-lobed ; thumb about one-fifth as long as 



third finger Desmodus, p. 177. 



Inner lower incisor with large median lobe and a minute outer and 

 inner lateral lobe ; thumb about one-eighth as long as third 

 finger Dicemus, p. 178. 



Genus DESMODUS Wied. 



1824. Desmodus Wied, Abbild. Naturgesch. Brasilien, r>te Lief., pi. and text. 

 1834—36. Edostuma d'Orbigny, Voyage dans l'Amerique Merid., p. vm. 

 1878. Desmodus Dobson, Catal. Chiropt Brit. Mus., p. 546. 

 1905. Desmodon Elliot, Check List Mamm. North Amer. Cont. etc., p. 530. 



Type-species. — Desmodus rufus Wied= Phyllostoma rotundum 

 Geoffrey. ' 



Geographic distribution. — Warmer parts of America, north to 

 southern Mexico. 



Number of forms. — The type species is the only form of Desmodus 

 thus far known. 



Characters. — Dental formula (Plates IX and X, fig. 3) : 



-2-1. 4 5-- . 1-1 1-1 1-1 1-1 



1 2- 1. -2-4 5--*2-2' c l-l'P m 2-2' 1U 1-1 — tj0 ' 



Upper incisors very large, almost completely filling space between 

 canines, the two teeth in contact anteriorly to beyond middle, strongly 

 projecting, with acute triangular point and long, very sharp, slightly 

 concave cutting edge. Lower incisors minute, straight, in pairs at 

 outer sides of two deep pits in which the upper incisors fit when jaws 

 are closed; the pairs separated from canines and from each other by 

 spaces about equal to their own length. The crown of each tooth is 

 deeply bilobed at the apex, the inner lobe slightly the larger. 

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