12. VESPERTILIO. 319 



Length (of an app. adult J preserved in spirit), head and body 

 l"-5, tail l"-4, head 0"-58, ear 0"-68, tragus 0"-26, forearm l"-2, 

 thumb 0"-18, third finger 2", fifth finger l"-5, tibia 0"-5, foot 0"-25. 



This species appears to be the representative of V. mystacinus in 

 North America, agreeing with that species in size, in the shape of 

 the head and ears, and in dentition, but distinguished from it by 

 the remarkably short thumb and smaller feet. 



Hah. North America west of the Rocky Mountains ; California ; 

 Texas. 



a, h. S ad., al. N. America. Smithsonian Institute [P.]. 



c. ad. sk. Mexico. Purchased. 



33. Vespertilio nigricans. 



Vespertilio nigricans. Wied, Beitr. Naturgesch Brasil. Ed. ii. p. 266 



(1826). 

 Vespertilio parvulus, Temminck, Monogr. Mammal, ii. p. 246 



(1835-41). 



About the same size as V. nitidus, but with smaller ears, shorter 

 muzzle, a larger thumb, and much darker fur. Crown of the head 

 abruptly and rather considerably raised above the face-line. Ears 

 shorter than the head, and narrow ; laid forwards the tips do not 

 quite extend as far as the end of the nose ; internal basal lobe 

 slightly rounded, its horizontal margin meeting the ascending inner 

 margin of the ear at a right angle ; middle third of the inner margin 

 convex, upper third straight; tip shortly rounded off, projecting 

 outwards, owing to the deep and abrupt concavity beneath occupy- 

 ing rather more than one third of the outer margin ; middle third 

 of outer margin abruptly convex, then flatly emarginate opposite 

 the base of the tragus ; lower third terminating in a distinct convex 

 lobe. Tragus much attenuated in upper one fourth and acutely 

 pointed ; inner margin slightly concave ; outer convex, very faintly so 

 in upper part ; a very distinct rounded lobule at the base of the outer 

 margin, succeeded by an emargination, shortly above which the tragus 

 reaches its greatest width (Plate XIX. fig. 9, ear, enlarged). 



Thumb moderate, with a well-developed claw ; feet small ; wings 

 to the base of the toes. Tail whoUy included within the inter- 

 femoral membrane. Termination of calcaneum indistinct. 



On the upper surface the face is nearly naked about the eyes and 

 in front of the ears, but the glandular prominences between the eyes 

 and the nostrils are covered with long straight hairs ; the fur of the 

 back extends to a very limited degree upon the wings, and upon the 

 interfemoral triangularly as far as the end of the third caudal ver- 

 tebra ; the sides of the membrane close to the legs are quite naked. 

 Beneath the wing-membrane is thinly covered almost as far as a 

 line drawn from the elbow to the knee-joint ; the fur of the abdomen 

 extends but to the root of the tail, the remainder of the interfemoral 

 is covered thinly with very fine, almost invisible hairs. Above, very 

 dark brown, slightly reddish brown towards the extremities of the 

 hairs ; beneath similar, the extremities paler. 



