166 BULLETIN 57, UNITED STATES NATIONAL MUSEUM. 



In general like Ardops, but skull with nasal region much depressed 

 between high supraorbital ridges; anterior nares directed chiefly 

 upward and extending fully halfway from front of premaxilla- 

 ries to point of juncture of supraorbital ridges which are not angu- 

 lated at middle, but extend in a nearly straight line from front 

 of orbit to sagittal crest; incisive foramina separated from roots 

 of incisors by space equal to their greatest diameter; inner upper 

 incisor with high slender crown, as in Phyllops; first and second 

 upper molars with low but distinct metaconule on surface of crown 

 between hypocone and metacone. 



Species examined. — This genus is known from the published de- 

 scriptions and figures only, as a second specimen has not been taken 

 and the type is now lost. The details in Wagner's lithograph of 

 the skull published by Peters are so complete as to leave no doubt 

 that the animal represents a peculiar genus, characterized particu- 

 larly by the form of the rostrum and .the presence of the well-devel- 

 oped metaconule in the first and second upper molars. These pecul- 

 iarities make it the most aberrant member of the restricted Steno- 

 dermine group. 



Genus PYGODERMA Peters. 



1863. Pygoderma Peters, Monatsber. k. preuss. Akad. Wissensch, Berlin, 



p. 83 (subgenus of Stenoderma) . 

 1865. Pygoderma Peters, Monastber. k. preuss. Akad. Wissensch., Berlin, 



p. 357 (genus). 

 1878. Pygoderma Dobson, Catal. Chiropt. Brit. Mus., p. H30 (genus). 



Type-species. — Stenoderma microdon Peters. 



Geographic distribution. — Warmer parts of America north to 

 southern Mexico. 



Number of forms. — Two species of Pygoderma are known — the 

 type, and the better known, P bilabintum Wagner. 



Characters. — Dental formula:- 



-2 3. 1. --345 6- . .2-2 1-1 2-2 2-2 no 



12-.1.-2-456- * 2=2 ' ° 1=1'^ 2=2' W 2=2= 28 - 



Upper incisors very unequal, forming a continuous row between 

 canines; the inner large, nearly half as high as canine, conical, 

 slightly higher than long, in contact basally, their tips wide apart, a 

 faintly suggested secondary cusp near middle of outer side ; the outer 

 minute, nearly flat-crowned, barely extending to cingulum of canine. 

 Lower incisors very small, closely crowded in a straight line between 

 canines, their subequal crowns deeply grooved transversely to the 

 tooth row. Canines low, stout, with prominent cutting edges and 

 wide postero-internal heel, which, in mandibular tooth bears a dis- 

 tinct secondary cusp; in both mandibular and maxillary tooth the 

 cingulum is moderately developed, forming a minute posterior cusp. 



