31 8 VESPERTILIONIDJ!. 



curvature of the tragus. The shape of the tragus agrees with that 

 of the species of the group of which V. emarginatus may be con- 

 sidered typical ; but the form of the ear-conch, the presence of a 

 postcalcaneal lobe, and other characters induce me to place it next 

 V. niuricola. 



New- World Species. 



V. mystacitms may be considered typical of all the known New- 

 World species of this subgenus, which differ from one another very 

 slightly, V. evotis and V. polytlirix being the only forms which may 

 be said to stand by themselves, and even these resemble V. mysta- 

 cinus in many respects. 



Moreover there appears to be a strong tendency to variability 

 within certain limits, so that certain individuals of a species often 

 depart considerably in the form of the ears, in the colour of the fur, 

 and in other respects from the type of that species. 



The discrimination of the American species is therefore very 

 difficult, and this difficulty is much increased by the small number 

 of specimens available for examination in museums (see remarks at 

 end of this genus, p. 329). 



32. Vespertiiio nitidns. 



Vespertilio nitidus, Allen, Proc. Acad. Sci. Philad. 1862, p. 247 f 

 Monogr. Bats of N. America (1864), p. 60. 



Ears very similar in shape to those of V. mystacinus, the outer 

 margin similarly deeply angularly emarginate, the only difference, 

 ajjparently, being that the inner margin is more convex in its middle 

 third, and the ear is thus proportionately wider. Muzzle long and 

 narrow, depressed as in V. mystacinus between the inner margin of 

 the ears ; the crown of the head slightly and abruptly vaulted behind 

 (Plate XIX. fig. 7, ear, enlarged). 



Thiimb very short, with a feeble claw. Peet small ; wings to 

 the base of the toes ; calcaneum long, ending in a small projecting 

 lobule. The extreme tip of the tail alone projecting. 



Pur long and dense, extending thickly upon the face to within a 

 short distance from the end of the muzzle, but covering the wing- 

 membrane along the sides of the body only. The fur of the back 

 extends backwards upon the base of the interfemoral to the end of 

 the third caudal vertebra, and laterally in a band, very thinly, in- 

 ternal to the tibia on each side almost to the ankle. Beneath, the 

 wing-membrane is clothed to a slightly greater extent than on the 

 upper surface, and about three fourths of the surface of the inter- 

 femoral is dotted with short, fine, thinly spread hairs ranged along 

 the transverse dotted lines. 



Pur, above, dark with reddish-brown tips ; beneath, similar, with 

 ashy extremities, the light-coloured extremities of the hairs con- 

 trasting strongly with their dark bases. 



Dentition quite the same as in V. mystacinus. 



