14 



only to mammals of difFerent orders. Among tlie rodents which I 

 have examined, the great species, as the Cai^ybara and the Beaver, 

 have much larger blood-corpuscles than the smallest species, as the 

 Bank Vole and the Harvest Mouse. 



2, ChARACTERS of SiX NEW GeNERA of BaTS NOT HITHERTO DISTIN- 



GuisHED. By j. e. Gray, Esq., F.R.S. etc. 



The first four genera belong to the tribe of Phyllostomina, or Nose- 

 leafed Bats. 



1. MiMON. 



Ch. gen. — Membrana interfemoralis magna, truncata. Ala latae, 

 margine anteriore lato, a summo talo extenso. Pedes elongati. 

 Crura nuda. Cauda mediocris, inclusa ; apice superiore, mediano. 

 Aures laterales, magnse. Mentum tuberculo parvo utrinąue sig- 

 natum ; tuberculis stria angusta divisis. Pollex longus, attenu- 

 atus ; articulis Eeąualibus. Dentes incisores f ; duo medii superiores 

 magni ; inferiores parvi, stipati. 



Ch. gen. — Interfemoral membrane large, truncated. Wings broad, 

 ■with a broad front margin from the upper part of the ankle. Feet 

 elongated. Legs bald. Tail moderate, enclosed : apex superior, 

 medial. Ears lateral, large. Ohin with a small tubercle on each 

 side, separated by a narrow gi-oove. Thumb long, slender ; joints 

 equal. Cutting teeth f; two middle upper large ; lower small and 

 crowded, 



In the collection at the British Museum there are two species of 

 this genus, viz. 1 . M. Bennettii = Phyllostomli Bennettii, Gray, Mag. 

 Zool. and Bot. vol. ii. p. 6 ; and 2. M. megalotis = Phyllophora mega- 

 lotis, Gray, Ann. and Mag. N. H. 1842, p. 257 ; Voy. Sulphur, t. v. 

 fig. 2. 



2. Trachops. 



Ch. gen. — Membrana interfemoralis magna, truncata. Ala; a summo 

 talo extensfe. Pedes osse calcis elongato insignes. Crura nuda. 

 Cauda mediocris, inclusa ; apice superiore, mediano. Aures per- 

 maguEe, laterales. Mentum et labia verrucosa, stria Isevis angusta 

 in medio mento. Dentes incisores ^ ; medii superiores magni, lati, 

 incisi ; inferiores irregulariter ordinati. 



Ch. gen, — Interfemoral membrane large, truncated. Wings from 

 the upper part of the ankles. Feet \vith the heel-bone elongate. Legs 

 bald. Tail moderate, enclosed ; apex superior, medial. Ears very 

 large, lateral. Chin and lips covered -vifith warts ; chin with a narrow 

 smooth groove in front. Cutting teeth | ; middle upper large, broad, 

 notched ; lower in an irregular series, 

 Type, T.fuliginosus. 



This species is characterized by its sooty-black colour. My son- 

 in-law, Mr. J. P. G. Smith, coUected it at Pernambuco, and sent two 

 females to the Brit. Mus. 



Vumpyris cirrhosum, Spix, Vesp. Braz. t. xxvi. f. 3, evidently be- 

 longs to the šame genus, if indeed it is distinct from the species above 



