Mammals from Tres Marias Islands. 19 



strongly inflated and arched ; the basisphenoid is strongly keeled along 

 the median line and its posterior fourth is abruptly elevated and has a 

 pocket or fossa on each side between the audital bullae, and on the same 

 plane with the basioccipital ; the zygomatic arches are slender, nearly 

 parallel, rods ; the upper canines divaricate so strongly that they are con- 

 spicuous when the skull is viewed from above ; the premolars are narrow 

 and well spaced ; the molars are small and weak. 



Measurements of type specimen, $ a( ^- : Total length (in flesh) 65 mm. ; 

 tail vertebrae (in flesh) 8 ; [following measurements from dry skin] fore- 

 arm 35.5 ; metacarpal of 3d (longest) digit 35.5 ; tibia 14 ; ear from ante- 

 rior basal angle 9 ; tragus from outer base 4.5. 



Remark*. — Mr. Nelson obtained 37 specimens of this new Glossophaga 

 on Maria Madre Id., where he found it inhabiting caves. Many of the 

 females contained partly developed embryos. 



Chceronycteris mexicana Tschudi. Tschudi's Hat. 



Chceronycteris mexicana Tschudi, Fauna Peruana, I, 72-73, 1844. Type 

 from Mexico. 

 "An immature specimen of this somewhat rare species is contained in 

 Mr. Forrei-'s Tres Marias collection." — (Mr. Thomas in Biologia Centrali- 

 Americana, 207, 1881). As already suggested, it would be worth while 

 to reexamine this specimen with reference to the possibility of its being 

 Glossophaga mutica. 



Lasiuius borealis mexicana (Sauss.). Mexican Red Bat. 



Alalapha mexicana Saussure, Rev. et Mag. de Zool., 2e ser. XIII, 91, 

 March, 1861. Type from Mexico. 



This species was not obtained by Mr. Nelson, but is recorded by Thomas 

 (under the old name Atalapha frantzii) as collected by Forrer on the Tres 

 Marias. (Biologia, Mammalia, 205, 1881.) 



? Phocaena communis Lesson. Common Porpoise. 



Mr. Nelson states that "a porpoise, supposed to be this species, was 

 common around the shores of the Tres Marias Islands, and also in bays 

 and at the mouths of sti'eams or lagoons along the coast of the mainland. 

 They were always seen in the belt of shallow discolored water within a 

 short distance of shore. As soon as the blue water was reached, with a 

 depth of over 40 fathoms, the other species, Prodelphinus longirostris, was 

 encountered. The present species was seen in school's of from ten to 

 thirty or forty individuals swimming in loose order. At Maria Madre 

 they came into the bay and close along shore early in the morning." 



Prodelphinus longirostris (Gray). Long-nosed Porpoise. 



Mr. Goldman shot a porpoise 12 to 15 miles off the islands, which Mr. 

 F. W. True has kindly identified as Prodelphinus longirostris (Gray). Mr. 

 Nelson states that there were probably 200 in the school from which this 

 specimen was secured, and that a number of such schools were seen 

 between San Bias and the islands. 



