The families akd otelsrERA ov bats. 135 



greatly reduced, though present. W-pattern even more distorted 

 than in Ohrotopterus, but still visible. Lower incisors very small, 

 about equal in size, forming a concave row between canines and not 

 rising to level of cingulum of the large teeth. Their crowns are 

 very low, slightly wider than long, with an ill-defined cutting edge 

 extending across middle. Lower canines very large, their bases 

 nearly in contact postero-internally, the posterior face of shaft and 

 outer portion of base flattened and slightly hollowed along region of 

 contact with upper canine; cingulum indistinct and without sec- 

 ondary cusps. Lower premolars compressed, with rather dull cut- 

 ting edges, the middle tooth (pm 3 ) fully in tooth row and about 

 half size of anterior premolar, the posterior (pm 4 ) distinctly larger 

 than pm 2 , the height of its cusps about equal to length of crown. 

 Lower molars still more highly modified than those of Ohrotopterus, 

 though in the same direction. In all three teeth the protoconid is 

 very large, nearly twice as high as the hypoconid ; in m 1 the para- " 

 conid and metaconid are so reduced as to appear as mere appendages 

 to the protoconid, the former scarcely breaking the contour of the 

 anterior cutting edge of the main cusp, the latter slightly less indis- 

 tinct. With the increased height of the tooth both of these rudi- 

 mentary cusps have been carried much farther above the base of 

 the tooth than the position they normally occupy. The entoconid, 

 however, remains in its usual position, though its size is less than in 

 Phyllostomus. In m „ the changes have not progressed so far, the 

 paraconid and metaconid retaining their distinctness and normal 

 positions with regard to the protoconid, though their size is reduced, 

 and they are carried much above the level of the small entoconid. 

 The posterior tooth is still less modified, though the same tendency 

 is shown, and the entoconid is absent. Skull considerably elongated, 

 the breadth of brain case less than one-third greatest length. Sagit- 

 tal crest well developed, especially in occipital region. Paroccipi- 

 tal expansions distinct, though not very large, strongly concave 

 beneath. Rostrum subcylindrical. Zygoma slightly expanded an- 

 teriorly and posteriorly. Audital bullae very" small, covering less 

 than half cochlear surface, their height at inner edge less than 

 diameter. Symphysis menti very long, the jaws strongly compressed 

 above it. Externally much like Phyllostomus, but with the chin 

 smooth as in Ohrotopterus, the muzzle much elongated, and the tail 

 absent; interfemoral membrane very wide; ear extending to ex- 

 tremity of muzzle ; fur normal. 



Species examined. — Vampyrus spectrum (Linnaeus). 



Remarks. — In the peculiar heightening and narrowing of the 

 molars this genus shows the most aberrant type of tooth structure 

 known in the subfamily. The tooth formula, however, has remained 

 somewhat primitive in the presence of a large pin „, a character 

 probably due to the elongated condition of the mandible. 



