1906. 



NATURAL SCIENCES OF PHILADELPHIA. 



339 



Lower surface of body pale brown, and peritoneum showing through 

 pale. A dusky humeral and caudal spot. Fins and iris pale brownish. 

 Length (caudal damaged) 2^ inches. Type, 



The other cotypes vary as follows : Head 2^ to 4, usually a little less 

 than 4; depth 3 to 3|; D. iii, 8, rarely iii, 7; A. iv, 21 to 26, and fre- 

 quently I, branched rays frequently 25; scales 30 to 35 (squamation 

 damaged); total length H to 2\ inches. 

 Astyanax diaphanus (Cope). Fig. 27. 



Tefragonoptenis diaphanus Cope, Proo. Amer. PhiJos. Soc. Phila., XVII, 

 1S77-7S (May 17, 1878), p. 691. Nos. 21,216 (type) to 21,218, A. N. S. P., 

 cotypes. Peruvian Amazon. Prof. J. Orton. Coll. of 1874. 



Predorsal region with an obsolete median keel, and postdorsal region 

 rounded. Preventral region rounded and postventral region trench- 

 ant. Rakers 7 + 10, slender, lanceolate, and longest a trifle more 

 than longest filaments which are about equal to diameter of pupil. 

 Isthmus narrowly triangular. Color in alcohol dull brownish, more or 

 less brassy, and especially broad band from eye to base of caudal. 

 Fins all dull brownish. Iris brownish-yellow. Length 2y^g inches. 

 Type. 



Fig. 27. — Astyanax diaphanus (Cope). 



The other examples show: Head 3f to 4; depth 3^ to 3^; D. ii, 8; 

 A. Ill, 17, I to 22, i; scales 33 in lateral fine to base of caudal and 3 

 more on latter; usually 4 scales in a vertical series between origin of 

 anal and lateral line; eye 2| to 2f in head; length about 2 inches with 

 damaged caudals. 



