1904.] NATURAL SCIENCES OF PHILADELPHIA. 251 



space has already been given to the taxonomic history of Mornioops^ 

 and Chilonycteris,^ only such points as differ will be noticed. The 

 genus was originally based on a specimen from Trinidad, and associated 

 by Gray with the following genera: Cheiromeles, Nyctino)nus, Molossus, 

 Thyroptera, Myopteris and Dididurus. Wagner, in 1843, described 

 a specimen of this genus, taken by Natterer at Cuyaba, Brazil, as 

 Chilonyderis gymnonotus, unaware that Gray had created a genus for 

 this type of bat. Later, in 1855, he apparently did not recognize his 

 species as a close relative of Gray's Pteronotus davyi, as he associated 

 the latter, which he, of course, had never seen, wdth Cheiromeles and 

 Dysopes in the section Macrura. The question as to the tenability of 

 the genus as distinct from Chilonyderis later caused a great amount of 

 shifting, the individual opinions of Peters, Dobson, Alston, and Thomas 

 differing as to the recognition of the genus. In 1892 Thomas de- 

 scribed a race of davyi from Jalisco, Mexico, basing it on the brilliant 

 fulvous coloration of the Mexican specimens, and their slightly smaller 

 size. Gill, in 1901, discovered the fact that Gray's Pteronotus was 

 preoccupied by Pteronotus Rafinesque, a synonym of Pteropus, and to 

 meet the deficiency he proposed the name Dermonotus. 



General Relations. — The genus Dermonotus is closely associated 

 with Mormoops and Chilonyderis, which constitute the subfamily 

 Mormoopince. The characters of the genus are such that recent 

 workers have all accorded it full generic rank, and as Gill has stated 

 {I.e.), modern systematic standards would fully allow the maintenance 

 of the genus as distinct from Chilonyderis. An interesting character 

 noted in this genus, as in the two allied genera, is the occurrence of 

 dichromatism. The two phases are quite marked, one being dull 

 chocolate-brown, the other rich fulvous. 



Key to the Forms. 



a. — First upper premolar longitudinal, not crowded; forearm aver- 

 aging 46.2 mm., davyi (Gray). 



aa. — First upper premolar nearly transverse, strongly crowded 

 between the canine and second upper premolar; forearm 

 averaging 44.1 mm., davyi fidvus (Thomas). 



Dermonotus davyi (Gray). 



1838. Pteronotus Davyi Gray, Mag. Zool. and Botany, II, p. 500. [Trini- 

 dad.] 



1843. Chilonyderis gymnonotus Wagner, Archiv fiir Naturgeschichte, IX, 

 bd. I, p. 367. [Cuyaba.] 



1 Proc. Acad. Nat. Sci. Phila., 1902, pp. 160-172, 

 Ubid., 1904. 



