1906.] NATURAL SCIENCES OF PHILADELPHIA, 469 



2^ to 2f in head ; pectoral If to 1|; ventral 3 to 3^; least depth of caudal 

 peduncle 3f to 4|; snout 4 to 4^ in head, measiu-ed from tip of upper 

 jaw; eye 3f to 5^; maxillary 2f to 3; interorbital space 2\ to 3f ; total 

 length of body (with slightly damaged caudal) 2f to 6^ inches. Alto- 

 gether 5 examples, the largest from between the mouth of the Rio 

 Negro and the Peruvian Amazon or Ucayale river. Of the others 2 

 belong to Orton's first collection (1873). The remaining 2 examples 

 are small. They are marked with a number of small round brownish 

 spots, each about the size of the pupil, and producing an effect simi- 

 lar to that seen on some examples of Ephippus argus. The caudal 

 is margined, within the lobes, and shaded basally with deep 

 brownish. Peruvian Amazon. Prof. J. Orton. Coll. 1877. 

 Serrasalmus humeralis Valenciennes. 



Serrasahno humeralis Cope, Proc. Acad. Nat. Sci. Phila., 1871 (1872), p. 



292. Between the mouth of the Rio Negro and the Peruvian Amazon or 



Ucayale River. Robert Perkins. 



Head 2|; depth If to ly^; D- 1, n, 14, i to 15, i; A. I, iii, 29, i to 30, 

 i; scales about 75 to 80 in lateral line to base of caudal, and 6 or 7 

 more on latter; 32 or 33 scales down from origin of dorsal to lateral 

 line; 34 or 35 scales down from lateral line to origin of anal; abdominal 

 scutes 30 to 32; mandible 2^ to 2^ in head; pectoral 1^ to If; ventral 

 2f to 2^; least depth of caudal peduncle 3^ to 3f ; snout 4 in head, 

 measured from tip of upper jaw; eye 4 to 4|; maxillary 2f to 2^; 

 interorbital space 3 to 3|; total length of body (caudals damaged) 

 4h to 5^ inches. Two examples. 

 Serrasalmus maoulatus (Kner). 



Serrasahno maculatus Cope, Proc. Amer. Philos. Soc. Phila., XI, 1869-70 

 (August 19, 1870), p. 566. Para. De Schulte Buckow. 



Head 2f ; depth If; D. I, ii, 12; A. I, iii, 29, i; scales about 77 in 

 lateral line to base of caudal, and 5 more on latter; about 31 scales 

 between origin of dorsal and lateral line; about 32 between origin of 

 anal and lateral Une; abdominal scutes 31; mandible 2^ in head; 

 pectoral If; ventral 2^; least depth of caudal peduncle 3f ; snout 4^ 

 in head, measured from tip of upper jaw; eye 4^; maxillary 2|; inter- 

 orbital space 3t; length of body 3f inches (caudal damaged). 



Serrasalmus aesopus (Cope). Fig. 53. 



Serrasalmo oesopus Cope, Proc. Acad. Nat. Sci. Phila., 1871 (1872), p. 269. 

 Type, No. 7,914, A. N. S. P. From the Maranon, between the mouth of 

 the Rio Negro, Brazil, and the Huallaga, Peru. Robert Perkins. 



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

 ured from tip of upper jaw. Body strongly compressed. Predorsal 

 region, and postdorsal to adipose fin, with slight median ridge. Chest 



