1906.] NATURAL SCIENCES OF PHILADELPHIA. 471 



anal and not surrounded by abdominal serratures. Color in alcohol 

 faded brownish, back from level with occiput deeper and without 

 brassy tint of lower surface of body. Body also with more or less 

 silvered or brassy reflections. Caudal with a rather broad pale 

 margin, then submarginally rather broadly deep dusky, otherwise 

 pale. Anal with margin rather broadly brownish and base also a little 

 brown. Other fins all more or less pale. Iris yellowish, brownish 

 above. Length 5| inches. 



Serrasalmus iridopsis (Cope). 



Serrasalmo iridopsis Cope, Proc. Acad. Nat. Sci. Phila., 1871 (1872), p. 268. 

 PI. 9, fig. 2. Type, No. 7,913, A. N. S. P. Ambyiacu River, Equador. 

 John Hauxwell. 



Width of head 2^ in its length ; interorbital space 3^, measured from 

 tip of snout. Body compressed. Head well compressed and robust. 

 Snout convex, and its length f its width. Teeth well developed in 

 jaws, those on mandible g~g, large. Each palatine with 7 teeth. 

 Tongue rather narrow, rounded in front and free. Interorbital space 

 broad and convex. Bones of head all more or less radiately striate. 

 Gill-opening forward to middle of eye. Rakers iv + v short denticles, 

 much shorter than filaments, which equal greatest exposed opercular 

 width. Color in alcohol brownish, sides silvered. Back with a num- 

 ber of rounded maculations, ranging in size up to that of pupil, and 

 fading out on flanks. Fins all pale brownish, dorsal and caudal a 

 trifle more deep in shade marginally. Iris pale brassy. Length 4^ 

 inches (caudal damaged). 



Although Cope states that the abdominal serratures are ' ' forty-one, ' ' 

 his figure would indicate altogether but 31 . Still as the type at present 

 shows 32 serrse, it is possible that some of those on the breast may have 

 fallen. 

 Serrasalmus immaoulatus (Cope). Fig. 54. 



Serrasahno immaculatus Cope, Proc. Amer. Pliilos. Soc. Phila., XVII, 

 1877-78 (May 17, 1878), p. 692. Cotypes, Nos. 21,503 (type; to 21,505, 

 A. N. S. P. Peruviau Amazon. Prof. J. Orton. 



Width of head 2\ in its length; interorbital space 2|- in head, meas- 

 ured from tip of upper jaw. Body strongly compressed, and pre- 

 dorsal and postdorsal regions, to adipose fin, wdth a slight median 

 ridge. Upper and lower surfaces of caudal peduncle a little compressed 

 convexly. Head compressed. Snout broad and surface convex. 

 Teeth —• Palatine teeth 7 on each side. Gill-opening forward 

 opposite middle of orbit. Rakers x + viii rounded scabrous processes 

 and each with a short denticulation. Filaments about equal eye. 

 Color in alcohol brownish, more or less dull and uniform or only with 



