542 Mi-. 0. Tliomas on new 



of the tootli-row from the front of the canine to the back of 

 ?».', but in J/, simus this breadth decidedly exceeds the same 

 longitudinal dimension. Distinct sagittal and lambdoidal 

 crests present. 



Upper incisors of about equal length ; the inner triangular 

 in section, with one longer anterior and two shorter posterior 

 cusps ; outer incisor with its slanting postero-external face 

 surrounded by five or six crenulations or minute cusps, but 

 how far these are the result of wear I am unable to say. 

 Small upper premolars drawn inwards from the tootb-row, 

 the second, minute, one entirely hidden behind the anterior 

 end of the large premolar. Middle lower premolar about two 

 thirds the height of the anterior one, which in turn is about 

 two thirds the height of the posterior. 



Dimensions of the type (measured on the spirit-specimen) : — 



Forearm 365 millim. 



Head and body 46; tail 33; head 15' 7 ; ear 12*5; tragus 

 on inner edge 4*5, • third finger, metacarpal 33, first phalanx 

 10, second phalanx 11; lower leg 14*5. 



Skull: occipito-nasal length in middle line 11"9; basi- 

 palatal length 10*3 ; interorbital breadth 4 ; mastoid breadth 

 7'5 ; palate length 5"4. 



Hah. Sarayacu, Peru. 



Type. Female (in spirit). B.M. no. 81. 5. 12. 2. Col- 

 lected in 1876 by Mr. W. Davis and presented by Messrs. 

 Yeitch. 



The short liair and comparatively stumpy build of this bat 

 give it so different an appearance to the other members of 

 Myotis that no one at first sight would suppose it to belong 

 to that genus ; but the detailed structure of the ears and the 

 characters of the teeth are typically those of Myotis and 

 there is no reason to distinguish it generically from that 

 group. 



No described species of the genus appears to have any 

 resemblance to it. 



Ariiheus Watsoni, sp. n. 



Size about as in A. cinereus, dentition as in A. glaucus. 



Kose-leaf similar to that of A. glaucus, but apparently 

 rather narrower. Ears higher and narrower than in that 

 species ; inner margin evenly convex, tip narrowly rounded ; 

 outer margin deeply concave in its upper half, then convex, 

 ending below in a slightly angular antitragal lobe. Tragus 

 more sharply pointed than in A. glaucus, and the projections 

 on the outer margin more prominent. 



Fur close and fine, extending on the jiroximal half of tjie 



