A MONOGRAPH OF THE BATS OF NORTH AMERICA. 159 



mastoid process is well detiiied, and is slightly produced downward. 

 The interval is smooth, but is deeply incised interiorly. Tlu; line of the 

 superior border of the anterior nasal aperture, if produced, would inter- 

 sect the first molar. The hard palate is inclined upward. The glenoid 

 cavity has a semblance of a iiedicle. The i)teryg<)id process is broad 

 and conspicuously produced. The tympauic bone conceals the cochlea. 

 The bony labyrinth being removed, the region of the semicircular canals 

 is seen to be wider than the cochlea. 



The corouoid process is rudimental, and but half the height of the 

 horizontal ramus. The masseric impression involves the coronoid and 

 reaches to the inferior border of the ramus. The angle is flat and does 

 not reach the line of the condyle, and is slightly deflected, so, when seen 

 above, is found to lie to the outer side of the condyle. A well-defined 

 post-symphysal rugosity is present. 



The general plan of the ethmoid plates resembles that of A. noveho- 

 racensis. The parts are, however, of greater height, the interval be- 

 tween the first and second endoturbinals being wider. The second 

 endoturbinal is relatively larger, and curved outward. This arrange- 

 ment causes the plate to present a concave surface outward, which 

 receives the swollen lower border of the third plate. The median 

 aspect of the first endoturbinal is straight; but the lateral surface is 

 deflected outward, and is imi^ressed on its entire surftice by the ec- 

 toturbinal which rests upon it, leaving only a raised rim of the 

 endoturbinal round its anterior half. The median surface of the pro- 

 duced i)ortion of the first endoturbinal is nearly as high as it is long. 

 The concave under surface embraces securely the maxilloturbinal. 



MaxUhiry teeth. — The single incisor adjoins the canine and j^roject- 

 ing slightly forward and inward. The median surface deeply and 

 sharplj' excavated and is in contour with the palatal notch. The canine 

 is wedged in between the incisor and the second premolar, posteriorly 

 fluted. Cingulum is entire; median excavation present. The first pre- 

 molar israinute, conical, placed well to inner side of the axis of tooth row. 

 The second premolar with broad cingulum, with scarcely perceptible 

 protocone, deeply fluted on buccal surface. The first molar resembling 

 Xyctinomus. The i)rotocone is of low development, much as in Ma- 

 crotus, but is acutely pointed at apex with oblique palatal surface, the 

 posterior commissure obscurely defined on the posterior aspect of tooth, 

 apparently not reaching beyond the a])ex of the second V. The first V 

 smaller than the second and more deeply fluted on buccal surface. 

 (Miigulum defined, buthypocone absent. The second molar much the 

 same as the first; the Vs are subeiiual. The third molar rudimental. 

 The i)iotoc<me and commissures are defined, but the posterior limit of 

 the first is imperfect, being defective in buccal half, while the second 

 V is absent. 



Mandibular teeth.— The incisors are crowded; the first is the widest 

 and coarsely serrate at the cutting edge, the second and third blunter 



