MAMMALS— NOCTILIONID.E— NYCTTNOMUS. 81 



No species of this genus appears to have been recorded from the United 

 States until Professor Baird described his M. californicus, based upon spec- 

 imens procured at Fort Yuma, Cal., by Maj. Gr. H. Thomas, United States 

 Army. Many others from Lower California, taken by Mr. J. Xantus, were 

 subsequently noticed by Dr. H. Allen under the same name. There is little, 

 if any, doubt, however, that this species is the same as the well-known West 

 Indian M. waterliousii. The only tangible distinction noted by Dr. Allen 

 is the color of the central portions of the hair — " fawn " instead of " dark 

 brown " — and this may readily have arisen from conditions of alcoholic 

 preservation or other circumstances. This identification is probably con- 

 firmed by Mr. J. A. Allen's discovery of a megadermatoid bat in Florida — 

 the first noted from our Atlantic region. It is difficult to find any tangible 

 specific characters in the M. mexicanus of De Saussure, after the careful con- 

 sideration of his article we have made. 



Fam. noctilionidae. 



Free-tailed Bats. 



Rostrum unappendaged. Nostrils circular. Alar membranes narrow, 

 deeply excised. Tail much longer or much shorter than femoral membrane. 



The typical Noctilionidines differ in figure remarkably from our ordinary 

 bats, owing to the narrowness of the wings and the immense extent of the 

 femoral membrane, which far surpasses the tail ; the free tip of the latter 

 resting against the parachute. The following genus, however, does not 

 show these latter peculiarities. 



Genus NYCTINOMUS, Geoffroy. 



Nyctinomus, Et. Geoffeov, Hist. Nat. de l'Egypte, 1814, ii.— Is. Geoffroy, 

 Ann. des Sc. Nat,, 1824, i, 337.— Castelnau, Expl. d'Arae>., Mammif., pi. 

 xii, f. 2.— De Saussure, Rev. et, Mag. Zool., 1860, 2S3. -Allen, Monog., 5. 



CHARS.-Teetli: I., l=i; C, H ; P-jJ^J M -> || = J7J = 30 " Up P el ' incisors "»»■ 



vergentbut separate; first premolar minute, second with a sharp inner cusp; lower in- 

 cisors sharp, bilobed, crowned; lower canines slender, cusped ; lower premolars of 

 equal size, unicusped. Skull inflated, crestless, papery; rostrum large. Snout broad. 

 prominent, piggish: lips thick, pendulous, furrowed; ears (in following species) united 

 over the vertex; tragus broad, obtuse, squarish. Great toe apart from the others. 

 Tail exserted beyond femoral membrane nearly half its length. 

 G z 



