1906.] NATURAL SCIENCES OF PHILADELPHIA. 473 



from tip of upper jaw. Body strongly compressed, and edges mostly 

 rounded. Head robust, compressed, and becoming constricted below. 

 Lips thin, cutaneous, and on each side of mandible forming anteriorly 

 a long flattened triangular flap equal to about f of orbit. In each 

 side of upper jaw externally 5 teeth, and each with a single cusp at 

 least. Transversely in front of upper jaw 4 bicuspid teeth connect- 

 ing lateral series. Mandible with 4 enlarged teeth transversely in 

 front, pair approximated at symphysis with a large posterior cusp 

 to each one, and 4 small teeth on each ramus graduated down 

 posteriorly. Tongue a little long, Interorbital space broad and con- 

 vex. Opercle with fine concentric strige. Gill-opening forward to 

 front rim of orbit. Rakers 20 + 24, slender, and longest equals pupil. 

 Longest filaments | of orbit. Tubes of lateral line simple. Vent 

 enclosed in serrse close in front of anal. Color in alcohol pale brown- 

 ish and sides more or less silvered. Fins all pale brownish, anal and 

 median caudal rays a trifle deeper. Sides of body with vertical 

 brownish streaks, and one about midway on side close behind lateral 

 line forming an ocellus. Iris slaty-white. Length 2^ inches (caudal 

 damaged). Type. 



The others show: Head 2i to 2f ; depth 1| to 1|; D. iii, 12, i to 15, i, 

 usually 14, i, sometimes 13, i, occasionally 12, i, and rarely 15, i; A, iii 

 or IV, 20, I to 23, i, usually 21, i or 22, i and only rarely 20, i or 23, i; 

 abdominal serratures 44 to 53; about 60 to 72 scales in lateral line to 

 base of caudal; snout 3f to 4 in head, measured from tip of upper 

 jaw; eye 3 to 3^; interorbital space 2^ to 2^; pectoral If to 2^; ventral 

 1| to 2^ ; total length of body lj\ to 2f inches. 



WAITEINA subgen. nov. 

 Type Myletes nigripinnis Cope. 



Anterior and posterior series of teeth well separated anteriorly in 

 upper jaw. 



(Named for Dr. Edgar R. Waite, formerly of the Museum at Sydney, 

 author of many contributions to the Ichthyology of Australia.) 



Colossoma nigripinnis (Cope). Fig. 55. 



Myletes nigripinnis Cope, Proc. Amer. Philos. Soc. Phila., 1877-78 (May 17, 

 1878), p. 693. Type, No. 21,124, A. N. S. P. Peruvian Amazon. Nauta. 

 Prof. J. Orton. 



Width of head 2 in its length ; interorbital space 2^ in head, measured 

 from tip of upper jaw. Body well compressed. Predorsal region 

 trenchant and edges of body otherwise mostly rounded. Head well 

 compressed, becoming constricted below. Snout broad and convex 



