428 PROCEEDINGS OF THE ACADEMY OF [May, 



predorsal scales; snout 3f in head measured from upper jaw tip; 

 eye 44; maxillary 2£; interorbital 2*. Abdominal seme 14 + 8. 

 This example otherwise agrees in most all respects. Length about 4 

 inches. 



Although this species agrees very well with the diagnosis of Serra- 

 salmo (Pygocentrus) notatus Liitken, 3 the latter is too insufficiently 

 described for positive identification. Liitken's examples were 9 

 inches long, and thus the smaller eye he gives as 3 in the interorbital 

 and 6 in the head, may be due to age ? Liitken also says the head is 

 3 in the body, without caudal. The only feature of coloration he 

 mentions is the black shoulder spot. My examples show the eye half 

 the interorbital width. 



(Iriyixa, brand, with reference to the large black post-scapular 

 blotch; 'epuffpdios, reddish, referring to the abdomen.) 

 Serrasalmus coocogenis sp. nov. Fig. i. 



Head 34; depth If; D. ii, 14, i; A. iii, 29, i; P. i, 14; V. i, 6; 

 scales in 1. 1. according to tubes 64 + 6; scales counted above 1. 1. 

 along its course 87+8; 33 scales above 1. 1. to dorsal origin; 34 

 scales below 1. 1. to anal origin; 30 scales below 1. 1. to ventral origin; 

 49 predorsal scales; head width about 1| its length; head depth at 

 occiput about 1; mandible 2f; first branched dorsal ray If; third 

 simple anal ray 2i; least depth caudal peduncle 3; upper caudal lobe 

 (tip slightly damaged) about 11; lower caudal lobe ly ¥ ; pectoral If; 

 ventral 2f ; snout 4 in head measured from upper jaw tip; eye 3i; 

 maxillary 3; interorbital 2j. 



Body deep, strongly compressed, contour slightly ovoid with greatest 

 depth at dorsal origin, predorsal edge a little trenchant, postdorsal 

 with only very slight median keel, abdominal edge trenchant with 

 23 + 10 serrae, and other body edges rounded convexly. Caudal 

 peduncle well compressed, length A its least depth. 



Head heavy, compressed, profiles similarly inclined, upper slightly 

 convex and then equally concave, lower slightly convex. Flattened 

 head sides scarcely constricted below. Snout surface convex, obtuse 

 in front, and its length about half its basal width. Eye circular, but 

 slightly elevated above middle in head depth and about first T 4 T in 

 head length between snout tip and hind edge of gill-opening. Mouth 

 broadly transverse, a little inclined, and with strong jaws. Maxillary 

 well inclined, rather small, its upper posterior end entirely concealed 

 by broad infraorbital, though it reaches about opposite front pupil 



3 Vidensk. Meddel. For. KjObenh., 1S74, p. 238 (240). 



