THE FAMILIES AND GENERA OF BATS. 161 



oped and nearly equal in size, the widening and shortening of the 

 crown displacing the latter cusp, so that both appear to be on ante- 

 rior side of tooth, the hypocone suggesting a protocone and the 

 protocone an enormously enlarged protoconule. Paracone and meta- 

 cone well developed, forming, with their commissure, the trenchant 

 outer edge of tooth. Outer cingulum obsolete in m 1 , well developed 

 in m 2 . Inner cingulum distinct in both and extending to tip of 

 paracone. Second upper molar slightly more than half as large as 

 first, its greatest length at middle instead of along outer edge, the 

 cusps all much reduced, particularly the metacone and hypocone, the 

 latter being shelf-like in form and sometimes practically absent. 

 Third upper molar reduced to the vanishing point, absent in some 

 species and present in others as a rounded flattish remnant smaller 

 than metacone of m 2 , close beneath which cusp it is situated. This 

 tooth is so small that its presence or absence has no effect on the form' 

 of the maxillary at back of tooth row. First and second lower mo- 

 lars alike in general structure, but first is the larger, and its greatest 

 width is at middle or posteriorly, while that of the second is in front. 

 The Stenodermine type of tooth is here seen in its most perfect devel- 

 opment, though Centurio presents a more extreme phase. The crush- 

 ing surface is large, finely and closely wrinkled, and slightly en- 

 croached upon by the cusps. Protoconid low, but long and well 

 developed, without cutting ridge on inner side. Hypoconid distinct 

 though low in m x ; obsolete or flat in m „. Metaconid high, narrow, 

 and subterete, connected with cingulum in m 2 , the cingulum passing 

 its base in m v Entoconid low but distinct, subterete. Between 

 metaconid and entoconid the cingulum occasionally rises to a dis- 

 tinct trenchant cusp. Third lowejr molar absent or present. When 

 present slightly larger than m 3 and with a small antero-internal 

 cusp, probably the protoconid, but area of crown not or scarcely 

 greater than that of metaconid of the other molars. Skull with 

 moderately wide, slightly elevated brain case, wide-spreading 

 zygomata and rather short, low rostrum. Length of rostrum 

 slightly more than half that of brain case and about equal to lach- 

 rymal breadth; depth through lachrymal region less than half 

 lachrymal breadth. Palate moderately wide, the distance between 

 the second upper premolars about equal to that from incisor to hypo- 

 cone of first molar. Ears separate. Noseleaf well developed. No 

 external tail. Interfemoral membrane narrow. Calcar short but 

 distinct. 



Species examined. — Artibeus coryi (J. A. Allen), A. glaucus 



Thomas, A. intermedins J. A. Allen, A. jamaicensis Leach, A. litu- 



ratus Lichtenstein, A. palmarum Allen and Chapman, A. parripes 



Rehn, A. phceotis (Miller), A. planirostris Peters, A. quadrivittatus 



25733— No. 57—07 m 11 



