AMEEICAN BATS OF THE GENERA MYOTIS AND PIZONYX 213 



finger, 93 and 91 ; fifth finger, 88 and 85 ; ear from meatus, 24.6 and 

 25; ear from crown, 20.4 and 19; width of ear (flattened), 16 and 

 16; tragus, 11.8 and 11. For other measurements see tables, page 214. 

 SpeciTTiens examined. — Fourteen, from the following localities : 



LOWER CALIFORNIA: Cardonal Island, Sal si Puedes Archipelago, 2 

 ale. (Paris; cotypes, examined by Miller in 1904), 3 ale. (A. M. N. H.) ; 

 Isla Partida, about 12 miles north of Cardonal, 7 skinned from ale. 

 (C. A.) ; Islas Eneantadas, 1 skin (Dickey). 



SONORA: Guaymas, 1 mummy (now in alcohol) (U.S.N.M.)- 



Remarks. — The striking peculiarities of Pizowyx vivesi render the 

 animal one of the most easily recognizable of American bats. These 

 peculiarities and more particularly the seemingly anomalous habitat 

 and geographical range make it appear to be possible that this bat 

 has some unusual mode of life. The original specimens were col- 

 lected by Diguet, in December, 1900, under stones heaped up by the 

 waves along the shore of Cardonal Island. Here the bats lived in 

 company with a species of petrel {Hdlocy'ptena microsonm Coues). 

 Diguet supposed that they fed on the excrement of the sea birds, but 

 he presented no evidence in support of this seemingly improbable 

 idea. The specimen in the United States National Museum was 

 found February 23, 1904, completely desiccated, on the beach at 

 Guaymas, Sonora, by the late William Palmer. The viscera had 

 been destroyed by insects, so that no trace of the animal's food could 

 be discovered. The digestive tract of the cotype in the British 

 Museum was examined for us by Mr. Martin A. C. Hinton, who 

 reports his inability to discover the slightest trace of food of any 

 kind. That of the adult female topotype in the American Museum 

 of Natural History was similarly explored by Mr. Eemington Kel- 

 logg, of the United States Department of Agriculture. He found 

 the stomach and intestines empty except for a few mites, some bat 

 hairs, and one small feather. While we are thus left in complete 

 ignorance as to the animal's food habits it seems not improbable that 

 the enlarged foot and claws, the relative freedom of the leg from the 

 wing membrane, and the elongation of the cusps of the teeth may all 

 be associated with a diet consisting at least partly of fish. The 

 resemblance of the leg, foot, and calcar to those of Noctilio., a bat 

 which is well known to devour small fish,^^ is obvious. 



" For a recent account of NocUUo's piscatorialism see Benedict, Journ. Mamm., vol. 7, 

 p. 58, Feb., 1926. 



