1904.] NATURAL SCIENCES OF PHILADELPHIA. 441 - 



Remar'ks. — This well-marked race of mexicanus can be easily recog- 

 nized by the smaller size, the weak second upper and distinctly crowded 

 third lower premolars. The Tres Marias specimens appear to be 

 inseparable from the mainland form. 



Specimens Examined. — Fifty-two ; twenty-seven skins, twenty-five 

 alcoholic individuals : 



Near Batopilas, Chihuahua. Four. (Biol. Surv.) 



Chacala, Dm-ango. Five. (Biol. Surv.) 



Bolanos, Jalisco. Twenty-one. (A. M. N. H., Biol. Surv., and Field 

 Columb. Mus.) 



San Pedro, near Guadalajara, Jahsco. Five. (A. M. N. H.) 



Ameca, Jahsco. Six. (Biol. Siu-v.) 



Maria Madre, Tres Marias Islands, Tepic. Eleven. (Biol, Surv.) 



Macrotus californicus Baird. 



ISoS. Macrotus Californicus Baird, Proc. Acad. Nat. Sci. Phila., p. 116. 

 [Fort Yuma, California.] 



1859. Macrotus calijornica Baird, Rep. U. S. and Mexican Boundary Sur- 

 vey, Vol. II, Pt. 2, Mamm., p. 4. PL 1, fig. 2. [Fort Yuma, California.] 



1864. Macrotus californicus Allen, Monogr. Bats N. Amer., p. 3, figs. 2 and 3. 

 [Fort Yuma, California; Cape St. Lucas, Lower California.] 



186.5. M[acrotus] californicus Peters, Monatsb. K. Preuss. Akad. Wissensch., 

 Berlin, 1865, p. 504. 



1875. Macrotus waterhousii Coues and Yarrow, Rep. Expl. Surv. W. 100th 

 Merid., V, p. 80. (Not of Gray.) 



1878. Macrotus waterhousii Dobson, Catal. Chiropt. Brit. Mus., p. 465. 

 [Cape St. Lucas, Lower California.] (Part.) 



1879. Macrotus xcaterhousvi Alston, Biol. Cent.-Amer., Mamm., p. 38. 

 (Part.) 



1894. Macrotus californicus Allen, Monogr. Bats N. Amer., p. 34, Pis. 1 and 2. 



[Fort Yuma, California; Cape St. Lucas, Lower California; near Tucson, 



Arizona.] 

 1901. [Otopterus'l californicus Elliot, Field Columb. Mus. Publication, Zool. 



ser., II, p. 420. 



Type Locality. — Fort Yuma, San Diego county, California. 



Distribution. — Arid region of the southwestern United States, Lower 

 Cahfornia and Sonora. Specimens have been examined from as far 

 east as Tombstone, Cochise county, Arizona, west as far as De Luz, 

 San Diego county, California, and from as far south as Camoa, Rio 

 Mayo, Sonora, and Cape St. Lucas. Caj^e St. Lucas and Sonoran speci- 

 mens are slightly smaller than topotj'pes, but are otherv^dse indistin- 

 guishable. 



General Characters. — Size large; form slender, ears extremely large, 

 subovate in outline ; limbs very slender; skull slender, rostrum narrow; 

 teeth weak; colors usually pale. 



Head. — Elongate, slender; rostrum rather attenuate; brain-case 

 moderately elevated. Ear very large, elliptical, when stretched for- 

 ward, exceeding the muzzle by a third the entire length of the append- 



