45. 8ERHASALM0. 867 



of the body, between ventrals and anal ; anal long. Head and body 

 compressed, more or less elevated, covered with very small scales ; 

 belly keeled, serrated. Cleft of the mouth of moderate width : teeth 

 large, compressed, sharp, pointed, with more or less lateral lobes^ in 

 a single series in the intermaxillary and mandible ; none in the 

 maxillary, which is short. Gill-openings very wide, the gill-mem- 

 branes being slightly united below the throat. Intestinal tract with 

 a single circumvolution. 

 Brazil, Guianas. 



The species have been referred to the following subgeneric groups : 



* No teeth on the palate ; teeth in the jaws serrated : Pygopristis, 

 M. & T., p. 367. 



** No teeth on the palate ; teeth in the-jawa simply cutting : Pygocen- 

 trus, M. & T., p. 368. 



*** A more or less complete series of teeth on each side of the palate : 

 Serrasalmo, Lac6p., p. 369. . 



* No teeth on the palate ; teeth in the .jaws serrated : Pygopristis, M. & T. 



1. Serrasalmo denticulatus. 



Serrasalmo denticulatus, Cuv. Mem. Mus. v. p. 371. 



punctatus, Schomburgk, Fish. Guiana, l. p. 223. taf. 17. 



Pygopristis denticulatus, Midi. iSf Trosch. Hor. Ichth. i. p. 34. tab. 9. 



tig. 1 (young) ; Cuv. Sf Val. xxii. p. 297. 

 fumarius, Mull. $• Trosch. I. c. p. 35. tab. 9. tig. 54; Kner, Denkschr. 



Acad. Wiss. Wien, 1860, xviii. p. 35. 



B. 4. D. 19. A. 35. V. 7. 



The height of the body is contained once and two-thirds in the 

 total length (without caudal), the length of the head nearly four 

 times ; snout obtuse, about as long as the eye. The second infra- 

 orbital bone is separated from the praeopercular limb by a naked 

 space, which is nearly as wide as the infraorbital. Abdominal ser- 

 rature composed of from thirty to thirty-four spinous plates. The 

 length of the adipose fin is two-sevenths of that of the dorsal ; none 

 of the fin-rays prolonged. 



Guiana. 



a, b, c. Adult and half-grown. British Guiana* Presented by Sir 

 R. Schomburgk and Dr. Hancock. 



2. Serrasalmo serrulatus. 



Pygopristis serrulatus, Cuv . §• Val. xxii. p. 300 ; Casteln, Anitn. Amer. 

 Sud, Poiss. pi. 38. fig. 3. 



D. 16. A. 33. 



The height of the body is one-half of the total length, the caudal 

 included. Adipose fin Bmall; none of the fin-rays are prolonged. 

 Vertical fins with blackish margins. 



Araguay, Amazons. 



