280 



CHIROPTERA 



temporal fossa at sauie level, its length about twice width ; 

 hamulars small and inconspicuous. Mandible long and straight, 

 its axis scarcely bent upward posteriorly ; symphysis deep, scarcely 

 or not subtended by a concavity in lower border of ramus ; 

 posterior portion of mandible low, the depth through coronoid 

 process barely equal to distance from front of coronoid to back 

 of condyle ; angular process large, straight, directed backward, 

 outward and downward. 



Teeth. — Relatively to size of skidl the teeth are rather large, 

 the lower molars in particular. The most obvious peculiarities 

 of the dentition as compared with that of other European bats are 

 the single, well developed incisor in each side of upper jaw, and 

 the presence oi a large hypocone, quite distinct from commissure 

 of jarotocone, in i«' and wi". Upper incisor simple, a little moi'o 



than half as high as canine, the 

 shaft set at an angle so that the 

 points of the two teeth are much 

 nearer together than their bases ; 

 cingulum faintly indicated in front, 

 better developed and forming an 

 incipient cusp postero-externally ; 

 posterior surface of shaft somewhat 

 flattened ; space between incisor 

 and canine aljout equal to greatest 

 diameter of smaller tooth. Lower 

 incisors three on each side, much 

 imbricated and closely crowded in 

 narrow space at front of canines, 

 their cutting edge barely rising to 

 level ■ of canine cingulum. The 

 inner and middle tooth sub-equal, 

 rather deeplj' bifid, the outer 

 barely equal to outer lobe of the 

 others, its apex faintly notched. 

 Upper canine moderately large, its crown area somewhat more 

 than double that of upper incisor, the general outline of its 

 base an irregular triangle with its longest side directed 

 inward, and with the postero-external side slightly concave ; 

 cingulum narrow but well developed throughout, not tending to 

 develop small cusps ; lower canine with no special peculiarities, 

 its cingulum tending to form a slight anterior cusp. Small 

 upper premolar in the tooth-row, usually in contact with canine 

 and separated from large premolar by a narrow space, its crown 

 area somewhat less than that of upper incisor, its cingulum and 

 cusp well developed, the cusp about one-fourth as high as shaft 

 of canine, triangular in outline when viewed from the outside, 

 with well developed posterior cutting ridge ; lower premolars 

 similar in form but larger, their crown areas sub-equal, the shaft of 

 the second higher than that of first and about equal to larger cusps 



FIG. 49. 

 Xyctiiiomus Icnlotis. Teetli X 5. 



