5. 0T0NYCTEK18. 181 



brane is covered thinly as far as a line drawn from the middle of the 

 humerus to the knee-joint ; beneath, to the same extent, but more 

 densely; the interfemoral membrane is naked on both surfaces, 

 except about the root of the tail. 



Above dark brown ; beneath similar, with paler extremities. 



Dentition similar to that of PI. auritus ; the outer upper incisors 

 are comparatively shorter ; the first and second lower premolars very 

 small, slender, and acutely pointed. 



Length (of an adult $ preserved in spirit), head and body 2", 

 tail l"-8, head 0"-75, ear l"-35 x 0"-85, tragus 0"-6 x 0"-17, forearm 

 l"-7, thumb 0"-35, third finger 2"-7, fourth finger 2"-3, fifth finger 

 2"-2, tibia 0"-75, calcaneum 0"-75, foot 0"-45. 



Hab. North America (Vancouver's Island, Utah, Missouri, Missis- 

 sippi, Alabama, S. Carolina, Florida). 



PI. townsendi is said by AUen to difi'er from PI. macrotis in being 

 larger, in the face being broader and more elongate, and in the 

 greater development of the glandular eminences on the sides of the 

 muzzle. These difierences appear to me to be due to age, PI. town- 

 sendi representing the perfectly adult condition of the species, in 

 which the glands of the muzzle are more developed. I find that the 

 size of the glandvdar eminences varies considerably in different spe- 

 cimens even from the same locality. 



This species agrees with PI. auritus in dentition and in general 

 form, the chief differences being the great development of the glan- 

 dular eminences on the sides of the muzzle (Plate XI. fig. 8) and 

 the less prominent lobe on the inner margin of the ear above its 

 base; and these characters have been used by Allen as distinguishing 

 marks of his genus Oorinorhinus. But in some specimens of PI. au- 

 ritus the glands on the sides of the muzzle form rounded prominences 

 rising slightly above the margins of the naked crescentie depressions 

 behind the nostrils. It is easy to conceive these prominences becom- 

 ing so large as to bend over and conceal the grooves, and this is 

 what we find in PI. macrotis. I cannot therefore consider this 

 species as the type of a genus distinct from Plecotus, 



a. $ ad., al. Vancouver's Islaud. Purchased. 



5". OTONYCTERIS. 



Otonycteris, Peters, MB. Ahad. Berl. 1869, p. 222. 



Crown of the head scarcely raised above the face-line ; nostrils 

 opening at the extremity of the muzzle by crescentie apertures con- 

 tinuous with small grooves on the upper surface of the muzzle, much 

 less defined than in Plecotus ; ears very large, separate ; tragus as in 

 Plecotus. 



11 11 1 1 O Q 



Dentition. Inc. -=^, c. j^, pm. g^, m. g^. 



Teeth like those of Nyctophilus. Skull very flat, slanting equally 

 from the occipital crest to the extremity of the nasals. 



