318 PROCEEDINGS OF THE ACADEMY OF [Juiie, 



pointed or upper rays longest, and reaching ventral. Ventral inserted 

 about opposite first third of base of dorsal. Vent close in front of 

 anal. 



Color in alcohol pale or dull brownish more or less silvered or with 

 brassy reflections. Back with pale or dull purplish reflections becom- 

 ing very dilute greenish on sides. Each scale more or less paler on 

 outer or exposed portion, so that rather pale longitudinal lines are 

 formed on back. Upper surface of head brownish, sides and low^er 

 surface silvered. Fins all pale brownish, dorsal with about eight dusky 

 cross-bands. Caudal with a median blackish band from center of its 

 base to tips of median rays, and each lobe with three oblique bands of 

 similar color, but broader anteriorly. Anal with three horizontal 

 dusky bands, lowest near tips of anterior rays, median beginning at 

 origin of fin, and upper at posterior rays. Pectoral and ventral plain. 

 Iris brownish. 



Length 4| inches. 



Type, No. 21,350, A. N. S. P. Lower Amazons. Prof. J. Orton. 

 Coll. of 1874. Prof. E. D. Cope. One example. 



This species is also apparently closely related to Prochilodus ijisignis 

 Jardine, but differs in the fewer blackish bars on the caudal lobes. It 

 will possibly prove identical with the examples recorded by Dr. Giinther 

 which have three dark bars on each caudal lobe. 



(Named for the Amazon river of South America, also written Ama- 

 zons and Amazonas. The name Amazon is said to be derived from 

 the Indian word Amassona or ' ' boat-destroyer, ' ' with reference to the 

 destructive tidal phenomenon or proroca.) 



HEMIODOPSIS subgen. nov. 

 Type Hemiodus microlepis Kner.' 

 This group is distinguished from subgenus Hemiodus Miiller and 

 Troschel by the small scales in a lateral count, at least 100 or more. 



{'H/ii, half; 68oh?, tooth; o4>t?, appearance, with reference to the 

 subgenus Hemiodus.) 

 Hemiodus microlepis Kner. 



Cope, Proc. Acad. Nat. Sci. Phila., 1871 (1872), p. 291. Between the mouth 



of the Rio Negro and the Peruvian Amazon. Robert Perkins. 



Cope, Proc. Amer. Philos. Soc. Phila., XVII, 1877-78 (May 17, 1878), p. 

 686. Peruvian Amazon. Prof. J. Orton. 



Head 4; depth 3y\; D. iii, 9, i; A. iii, 9, i ; scales about 105 (squama- 

 tion injured) in lateral line to base of caudal, and 7 more on latter; 

 about 24? scales obliquely back from origin of dorsal to lateral line; 

 about 12? scales between lateral line and origin of ventral, and about 

 same number between former and origin of anal ; snout 3^ in head ; eye 



