116 BULLETIN 13, UNITED STATES NATIONAL MUSEUM. 



yond the region of the roots of the third premolar in a manner miieli 

 ihe same as in T^ hesperus. A distinct lachrymal cana m the orbit i. 

 seen, but no concavity lies aboveit. The line produced ^^ownward from 

 the upper border of the anterior nasal aperture intersects the dental 

 arch directly back of the canine tooth. The paroccipital process alnn.st 

 reaches the level of the lower border of the occipital condye. The 

 region between the paroccipital process and the mastoid is not elevated; 

 it\^etains a deep incision iuferiorly, and equals one-seventh of the 

 P-reatest length of the skull. 



The space between the swelling over the roots ot the upper mcisors 

 and canine is without groove. (See A. serotinus^ The upper border of 

 the anterior nasal aperture is rounded. {See A. serotmns.) 



There is no post-maxillary process. The tympanic bone with a sma 1 

 anteriorly produced process on the base. The anterior palatal notch 

 reaches to a line intersecting the middle ot the canine tooth. The 

 heioht of the coronoid process above the level of the condyle greater 

 than the width of the horizontal ramus. The interval between tlie 

 ano-le and the condyle is semicircular. The impression for the masseter 

 muscle is deep, and sharply defined interiorly. Angle on line with the 

 outer third of condyle, and is therefore scarcely deflected. 



In»er ear -Superior semicircular canal, free; the external, scarcely 

 free; a small opening is seen in the bone almost occupying loop. A 

 small portion of the cochlea is exposed on the side of tae skull, just 

 below the union of the occipital with the squamosal. 



The openings of the septoturbinal space are confined to a large fora- 

 men, placed just in advance of the nonperforate space. Kear to the 

 septum, at the anterior portion of the space, is seen a group of foramina 

 advancing well to the front. Directly opposite the beginning of this 

 series to the lateral side,is the group of foramina for the first endotur- 

 binal plate, while in front of the latter lie two foramina for the single 

 ectoturbinal plate. The arrangement is the same in T esperugo The 

 ectoturbinal is as in NoctnUnia nocUda, with the exception that it is 

 deflected a little more outward. The first endoturbinal is acuminate, 

 with a uniformly sloping border. On the medium service the plate is 

 not visible below the second and third plates. The second plate is as 

 in N.noctula. The third is longer than wide. ,., ^ ^ 



Maxillary teeth.-The maxillary central incisor long, chisel-shaped, 

 slightly inclined medianly in young and young adults, but to a less de- 

 gree than in A. .erofm».; bifid on the cutting edge, the outer nodule 

 being larger. The cingulum narrow, uniform, entire. The lateral in- 

 cisoirudimental, conical, cingulumbroad,uniform,entireThemcisors 



exhibit considerable variation. Some of these are exhibited in accom- 

 T^anvino- figures. (PL xv tigs.8-10.) The modifications consist m propor- 

 tion of dngulum to length of crown in the size of the small cusp on the 

 cutting surface of the central tooth, and in the size and degree of concav- 

 ity on the outer border of the lateral tooth. In one example (specimen 



