NYCTINOMUS 



279 



slight convexity over anterior two-thirds of brain-case, and a 

 more abrupt though not very conspicuous swelhng posteriorly, 

 the two convexities separated by a narrow concavity ; general 

 direction of dorsal pi'otile more nearly horizontal than in any 

 other European bat, since the depth of occiput through condyles 

 is scarcely greater than that of rostrum through anterior portion 

 of first molar. Brain-case low and wide, its depth at middle 

 about half mastoid breadth, its surface smooth and evenly 

 rounded, with faintly indicated sagittal crest posteriorly and 

 median groove between lateral swellings anteriorly ; lambdal 

 crest evident though not high ; outline of brain-case when 

 viewed from above a somewhat triangular ovate owing to the 

 rather squarely truncate posterior border and the strong contrast 

 between the wide mastoid region and narrow iaterorbital con- 

 striction ; floor of brain-case with median ridge and lateral 

 depressions posteriorly, the basisphenoid 

 with two shallow but rather well-defined 

 pits about as large as glenoid surface ; 

 auditory bullae leather large, deeply emar- 

 ginate on inner side so that cochlea is 

 conspicuously exposed, the region in 

 front of middle of meatus reduced to a 

 narrow ring barely more than one-third 

 as wide as meatus, the extreme anterior 

 border with a flange-like inward-curved 

 projection. Interorbital region long, sub- 

 cylindrical, a little wider at lachrymal 

 level than posteriorly, but scarcely enough 

 so to impart a distinctly hour-glass general 

 form ; least interorbital breadth slightly 

 greater than breadth of tubular narial 

 region and slightly less than that across 

 roots of canines. Zygoma simple, not 

 bent upward, its margin with a barely indicated expansion behind 

 middle. Rostrum proper short and deep, not well differentiated 

 from interorbital region, the distance from orbit to front of pre- 

 maxillary about equal to depth at front of m^ ; lachrymal ridge 

 short but well defined, the small, inconspicuous anteorbital fora- 

 men and minute lachrymal foramen opening forward under its 

 anterior edge, at level of middle of large premolar ; nares with 

 distinctly tubular lateral margins sepai-ated from roots of canines 

 by evident grooves, the dorsal emargination extending about half 

 way to lachrymal level. Palate moderately wide, noticeably 

 concave laterally, the anterior emargination small, about as deep 

 as wide, its posterior border scarcely extending behind level 

 of front of canine ; posterior border of palate double emargi- 

 nate with well developed median projection, the emarginations 

 extending forward to level of posterior margin of »i^ ; mesop- 

 terygoid space large, its width anteriorly equal to that of 



FIG. 48. 



Nyctinomus teiiiotis. 

 Nat. size. 



