4 UNITED STATES AND MEXICAN BOUNDARY. 



1. MACROTUS CALIFORNICA, B a i r d .—California Leaf-nosed Bat. 



J\Iacrotus californlca, Baird, Pr- A. N. Sc. 1858. 



The ears of this species are very large^ scantily haired, ovate and rounded at the tip. Their 

 outer edge extends forward to a little behind and below the eye ; the inner anterior edge is 

 partially free ; the two ears are connected by a membrane, which takes its rise about one- 

 twentieth of an inch behind the anterior free edge of the ear, and is united to the corresponding 

 strip of membrane of the opposite side, so as to form a kind of roof over the middle of the head, 

 the entrance posterior. The tragus is narrow, lanceolate, naked, one-third the height of the 

 ear. The nasal appendage is short, but rather higher than wide, and extending on the side 

 and beneath the nostrils as a narrow margin. It is coated rather closely with short hairs. The 

 lower jaw is slightly fissured anteriorly, with a small narrow wart on each side the fissure; 

 a groove or furrow extends from the fissure along each side the lower jaw. 



The feet are entirely free, the spur about as long; the membrane extending between the spurs 



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-**-' "^ y — j^ ------ ^j , ^j 



slightly concave, leaving the extremit} of the tail free for the last joint, or for about 



one- 



sixth its total length. 



The general color is a pale brownish grey ; darker above than below. 



Length to occiput 1.00 



r 



Length to root of tail 2,60 



LengtTi of tail 1.50 



Length of tragus .42 



Length of leaf of nose 30 



"Wing from carpal joint 3.00 



Length of ears 1.10 | Fore arm 2.00 



This species closely resembles the M. tvaterJiousii of Gray, from the West Indies. It diiFers, 

 however, in the longer tail and shorter appendage of the nose, as well as in the widely different 



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locality. 



2347. Fort Yuma, California. Major G. H. Thomas. 



Family GYMNOEHIM. 



Ch. — ^Nose simple, without a foliaceous appendage embracing the nostrils; teeth cuspidate. 



It is in this family that all the North American bats, with the exceptions above referred to^ 

 are found, although they do not embrace many different generic forms. The number of species is 

 quite large, though not well ascertained, over thirty being recorded in the books. 



In the great uncertainty attending the true characteristics of North American bats, as described, 

 and the necessity of carefully identifying the species of the eastern States, I have been unwilling 

 to attempt the description of the bats of western America at the present time. I have, accord- 

 ingly, figured but two species ; the one, Macrotus calif ornicus ; the other, Fespertilio ^pallidus, 

 of Major Leconte ; the description of which, taken from this eminent author, I subjoin. 



2. VESPERTILIO PALLIDUS, Leconte.— Yellow Bat. 



'^perl 



" Upper Jaw. Incisorsl — 1, large, Mmple. Canines 1 — 1, a little concave on the outer side, with an internal, basal, rather blunt 

 cusp. False molars 1 — 1. Molars first and second, as in all the others; the third with four cusps, three of them transverse, 

 the interior one smaller, aod one posterior, 



" Lower Jaw. Incisora. 4, False molars 2—2, the anterior one smaller, rather interior. First and second molaraas in others 

 the third with three cusps, not transverse, the interior one larger, and transversely deeply emarginate. 



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