THE SHORE FISHES OF PERU 367 



Genus EUTHYNNUS Lutken, 1883 



This genus differs from Katsuwonus in having teeth on the palatines 

 and sometimes on the vomer, and with respect to internal structures 

 described by Kishinouye (1923, p. 452). Vomerine teeth are absent 

 in the species herein described, and the palatine teeth are scarcely 

 discernible. The species may be distinguished from Katsuwonus by 

 the fewer gill rakers, there being 25 to 27 on the lower limb of the first 

 arch in Euthynnus alletterata and 36 to 40 in Katsuwonus pelamis. 



Two species have been recognized from the Pacific coast of the 

 Americas, the second species E. lineatus Kishinouye differing from the 

 one herein described in having teeth on the vomer. 



EUTHYNNUS ALLETTEKATA (Rafinesqne) 



Scomber alletterata Rafinesque, 1810, p. 46, Palermo (original description). 

 Gymnosarda alletterata Jordan and Evermann, 1896, p. 869, fig. 366 (description; 



range; synonymy). — Meek and Hildebrand, 1923, p. 311 (synonymy; 



decription, based on specimens from the Atlantic coast of the United States, 



Hawaii, Java, and the Philippines; range). 

 Euthynnus alletterata Kishinouye, 1923, p. 457 (diagnosis in key). 



Head 3.25, 3.3; depth 3.85, 3.85; D. XIV-11-VIII, XIV-11-VIII; 

 A. II, 11-VII, II, 11-VII; P. 26, 27. 



Body robust, its greatest thickness about two-thirds its depth, 

 tapering strongly posteriorly; caudal peduncle very slender, depressed, 

 with a moderately strong lateral keel, 13.7, 13.7 in head; head com- 

 pressed, convex above; snout rather long, pointed 3.5, 3.6 in head; eye 

 round, 6.2, 6.3; interorbital 3.4, 3.5; mouth large, oblique, terminal; 

 maxillary reaching a little beyond middle of eye, broad, slipping partly 

 under preorbital, 2.55, 2.65 in head; teeth in jaws in a single series, 

 short and strong, none on vomer, scarcely discernible on palatines; gill 

 rakers nearly as long as eye, 25, 27 on lower and 9, 9 on upper limb of 

 first arch; lateral line wavy anteriorly, curved downward and becom- 

 ing straight and midlateral in position under the second or third 

 dorsal finlet; scales present anteriorly in region of pectoral, extending 

 on back to second dorsal, reduced scales in lateral line, and a somewhat 

 pointed area of scales extending to or beyond tip of pectoral fin; first 

 dorsal with slender spines, the first ones long, the posterior ones short, 

 scarcely extending above dorsal groove, the first one 1.85, 1.9 in head, 

 origin of fin little behind base of upper rays of pectoral, its distance 

 from tip of snout 3.0, 3.1 in length; second dorsal somewhat elevated 

 anteriorly, with deeply concave margin, its origin about equidistant 

 from origin of first dorsal and fifth or sixth finlet ; anal origin under or 

 somewhat in advance of vertical from first dorsal finlet; ventral con- 

 siderably shorter than pectoral, inserted slightly posterior to pectoral, 

 its distance from tip of mandible 2.6, 2.9 in length; pectoral moderately 

 pointed 1.7, 1.75 in head. 



Color very dark blue above; this color merging into silvery along 



