new Bat from Peru. 573 



Viewed from the side, the rostrum is seen to be much flat- 

 tened as compared with that of Rhogeessa. The flattening is 

 visible in dorsal view also, though less conspicuous. Ant- 

 orbital foramen separated from rim of orbit by a wide space, 

 in the middle of which the relatively large lachrymal foramen 

 opens directly outward. Bony palate as in Rhogeessa tumida, 

 except that the backward extension behind plane of molars is 

 shorter and without median spine. 



Teeth. — Except in (heir uniformly smaller size and in tlie 

 absence of the outer incisors the mandibular teeth do not 

 differ appreciably from those of Rhogeessa tumida. The 

 maxillary molars, on the other hand, are immediately distin- 

 guishable by their greater development. The first and second 

 are each provided with a distinct hypocone separated from 

 the commissure of the protocone by a deep notch. In Rhoge- 

 essa the hypocone is so merged with posterior commissure 

 of protocone as to have practically lost its identity. Third 

 molar much broader than in Rhogeessa tumida, owing to the 

 presence of a well-developed metacone. 



Measurements. — External measurements of type (skin) : 

 head and body 42 millim.* ; tail 32* ; tibia 10 ; foot 5 (4*2) ; 

 calcar 11; forearm 33'4 ; thumb 4'6; second digit 27; 

 third digit 56 ; fourth digit 48 ; fifth digit 38. 



External measurements of an adult, female from Chosica, 

 Peru (in alcohol) : head and body 39* ; tail 34*; tibia 10; 

 foot 5 6; calcar 12; forearm 326. 



Measurements of an adult female from Tolon, Peru (in 

 alcohol) : head and body 36'4 ; tail 33; tibia 11; foot 5; 

 forearm (broken) 31 ; ear from meatus 12 ; ear from crown 

 10'4 ; width of ear 11"6; height of tragus from anterior 

 base 1-8. 



Cranial measurements of type: greatest length 12'6; 

 basal length 11*4; basilar length 9; zygomatic breadth 7; 

 lachrymal breadth 4*8 ; least interorbital breadth 3 ; greatest 

 breadth of brain-case above roots of zygomata 6 - 6 ; depth of 

 brain-case 4*4; mandible 8'6 ; maxillary tooth row (exclu- 

 sive of incisors) 4*4 ; mandibular tooth-row (exclusive of 

 incisors) 5. 



Remarks. — While Tonwpeas ravus is so readily distinguish- 

 able from other bats as to require no special comparisons, its 

 relationships are much involved. The general external struc- 

 ture, so far as wings, membranes, feet, and tail are concerned, 

 shows no departure from a strictly Vespertilionine type. The 

 somewhat tubular nostrils and the broad upper lip show, on 



* Collector's measurement. 

 Ann. & Mag. X. Hist. Her. 7. Vol. vi. 38 



