130 BULLETIN 43, UNITED STATES NATIONAL MUSEUM. 



maining teeth iiiucli as iu Yesperuyo carolinensis. excepting iu the last 

 mohir, where a trace of the last limb of the second V is discernible. 

 The drawing exhibits this rudiment a little longer than is the average. 



Mandibular teeth. — The lower incisor with third tooth contiguous with 

 second incisor and with canine. The first premolar in linn contact with 

 the canine. In other resi)ects the teetli are as in Ves2)eru(ju carolinensis. 



SJcull. — No trace of posterior temporal crests or sagittal crests are 

 seen. The anterior temporal crest is well defined. The mesencepha- 

 lon three and one-third times the length of the skull. No nasal emi- 

 nence is seen; a shallow groove is present at the anterior third of the 

 face vertex; back of this groove lies a well-defined oval pit. The infra- 

 orbital canal is as in A.fusous Both the groove and the pit are sharply 

 limited at the sides by lateral ridges. The upper surface of the max- 

 illa is depressed.* The paroccipital process is rudimentary and scarcely 

 visible. The tympanic bone is incomplete above. 



Notes 071 the sl-eleton. — The bones much the same as in Vesperugo 

 carolinensis. The free end of coracoid with long process on the vertical 

 side instead of the small tubercle of the species just named. The pec- 

 tineal spine ot the innominate bone aciculate, long, equaling one-fifth 

 the length of the ilium. The thyroid foramen is subround, the ischium 

 narrow, the tuberosity prolonged, the posterior border of the innomi- 

 nate nearly horizontal. Sacrum composed of four elements. 



Rabitat. — Vesper mjo Jiesperus ranges from the low, hot plains of Mexico 

 upward into the Californian basin through the valley of the Colorado 

 Eiver and the surrounding country. Dr. Merriam informs me that it is 

 never found in the mountains and the limit of its distribution is sharply 

 limited to the lower ranges of hillsides and to the plains. According 

 to the same observer (N. A. Fauna, No. 3, 1800, 37) V. liesperns is found 

 in swarms in the Grand Canon of the Colorado River. It inhabits the 

 crevices of the cliffs and is often found drinking from springs. " The 

 flight of this species is so SAvift and zigzag that it is a very difticult 

 species to shoot in the rapidly failing light. The young, as usual among 

 bats, fly more slowly and steadily and are easily killed." It inhabits 

 crevices in cliffs and begins to fly before dark in the evening, at which 

 time swarms of them come up over the brink of the canon and flit 

 about among the pines and x)inou. 



Measurements. 



[San Sebastian, Cal. d Cal. Acad. Sci.] 



Millimeters. 



Head and bodj' (from crown of head to base of tail) 26 



Length of arm 16 



Length of forearm -o 



First digit : 



Length of first metacarpal bone 1 



Length of first phalanx ^i 



Second digit: 



Length of second metacarpal bone ^" 



Length of first phalanx 1 



*The hard palate is depressed, saucer-shaped, i. c., is eriually concave from before 

 backward and from side to side. 



