A MONOGRAPH OF THE BATS OF NORTH AMERICA. 149 



pressed medio-laterally. It is slightly convolute outward at its base 

 and concave on its lateral surface. The first endoturbinal is abruptly 

 acuminate anteriorly, and straight on its median, lateral, and under 

 free surfaces, the last named being concave inferiorly. The second en- 

 doturbinal plate is oblique, and slightly inflated at its anterior end. 

 Its lower border forms the inferior edge of the median series of plates. 

 The third endoturbinal is triangular in shape, and is one-half the size 

 of the preceding. 



Teeth. — Teeth the same as in A. cinerea, with the exception the lower 

 incisors are less crowded and serrate throughout. Some specimens show 

 a degree of crowding greater than that exhibited in the drawing. The 

 anterior prolongation on the lingual aspect of the lower second premolar 

 is somewhat exaggerated. The incision between the paraconid and 

 hypoconid does not reach to the level of the basal cingula.* 



The milk upper incisors are carried outward, canine form, and four in 

 number. The lower incisors are unequal, the first tooth being the 

 smallest and simplest, the third the largest and most complex. The 

 lower canine is curved backward and furnished with a large basal cusp. 



Mr. Gr. S. Miller has sent me, from Nassau, a skull of A. noveboracensis 

 possessing the remarkable peculiarity of the left maxillary incisor hav- 

 ing two distinct cusps instead of one. Close examination was required 

 before it could be seen that two left incisors were not present. 



J^otes on the sl-eleton. — The end of the coracoid process of the scapula 

 is scarcely wider than the base; the spine is but little curved and is 

 furnished with a tubercle at the middle. The region of the semicircular 

 canals of the bony labrynth is scarcely wider than the cochlea, and is 

 without lateral expansion. The epicondyle of the humerus is produced 

 as a spine. The sternum is provided with a large ventral crest at the 

 anterior third of the prosternum; the lateral process is one-half the 

 length of this segment. The distal rudiment of the ulna is in the form 

 of a reverted spine, which is occasionally united to a crest projecting 

 from the radius, thus converting the notch that is defined between the 

 ulna and the radius into a foramen. The radius is quadrate, in trans- 

 verse sections; it retains a groove for the extensor tendons. The pec- 

 tineal spine is quadrate and as high as the upper border of the acetab- 

 ulum. The calcar is firmly osseous. The fourth metacarpal bone is 

 not concealed when the third and fifth bones are approximated; the 

 first metacarpal bone lies near the center of the carpal region ; the 

 second metacarpal is broad and stout, resulting in defining a small 

 second space between it and the second metacarpal. 



Bemarhs on sex. — The females as a rule are a little largef than the 

 males, and, when fully adult, retain at the lower border of the chin- 



* Maj. John Leconte (Proc. Acad. Nat. Sci. Phila., 1853), in describiuj^ the teeth of 

 this species, states that the canine is hollowed out behind, with a perpendicular 

 septum dividing the concavity for its whole length. The premolars are concave on 

 the outer and inner surfaces. 



