THE FAMILIES AND GENERA OF BATS. 
163 
Number of forms.-- Three species are known, Ardrops niehollsi 
(Thomas), A. montserratensis (Thomas), and A. lucice (Miller). 
Characters . — Dental formula : 
-2 3. 1. - -3456T .2-2 A - 1 _ 2 - 2 
1 2 1. - 2 - \ 5 6 7 * 2-2’ c 2-2’ 
m 
3- 
3- 
3 
= 32. 
Upper incisors proportioned about as in Artibeus and forming a 
straight line between canines, the outer rising barely to level of cin- 
gulum of canine, its crown broader than long, deeply grooved on 
anterior face, its cutting edge entire and with faintly indicated 
cusp, but scarcely oblique, the inner about twice as high *as outer, but 
with its length nearly equal to its height, its posterior surface con- 
cave, its cutting edge rising to a blunt main cusp on inner side and 
sometimes showing a rudimentary second cusp on outer side. Lower 
incisors subequal, smaller than upper, the crowns projecting conspic- 
uously forward beyond roots, the anterior surface oblique, higher 
than wide, deeply grooved, the groove passing through cutting edge 
and short posterior surface. Canines stout, scarcely higher than 
large premolars {pm 4 and pm±), the lower with well developed 
postero-external talon, this slightly indicated in upper. Anterior 
upper premolar ( pm z ) essentially like canine, but not as high, 
and Avith better developed postero-external cingulum cusp. Pos- 
terior upper premolar {pruA) about as high as canine, but Avith 
longer base and Avith a conspicuous, deep, postero-internal con- 
cavity for reception of protoconid of first lower molar; posterior 
cutting edge with large secondary cusp near middle in addition 
to the basal talon. Anterior lower premolar ( pm 2 ) essentially 
like anterior upper premolar. Posterior lower premolar [pm 4 ) 
more nearly resembling loAver canine and Avith similar large 
postero-external talon, but the length of croAvn greater in propor- 
tion to the height, and the shaft thicker basally. Upper molars as 
in Artibeus except that hypocone of m 2 is relatively larger and 
more distinct from protocone, Avhich it nearly equals in height ; m 3 
about as large as metacone of m 2 , its surface concave, with a minute 
inner cusp and two outer cusps, one of the latter situated distinctly 
inward from the cingulum. A distinct though small median cusp 
on outer side of m 2 is possibly a rudimentary mesostyle ; outer 
cingulum obsolete, but inner unusually Avell deA^eloped, that of m 1 
passing around anterior base of paracone. First lower molar dif- 
fering noticeably from that of Artibeus in the relatively much larger 
and higher protoconid, the inner side of which is provided with a 
high ridge which obliterates metaconid and extends baclvward to 
beyond middle of crown; entoconid high and distinct, relatively 
much larger than in Artibeus. Second lower molar more nearly 
resembling that of Artibeus , but with the protoconid, metaconid, and 
