368 BULLETIN 189, UNITED STATES NATIONAL MUSEUM 



middle of side; side of head, chest, and region around ventrals and base 

 of pectoral a rather dirty white; one specimen (the larger one) with 

 short black bars, running upward and backward above lateral line, and 

 with obscure dark longitudinal streaks below lateral line, these broken 

 up into large black spots anteriorly in space between pectoral and 

 ventral fins. The dark markings missing in the other specimen at hand 

 except for a few dark blotches between pectoral and ventral fins. 

 Spines of first dorsal dark, the membranes white; ventral fin dirty 

 white on outer surface, dusky on inner side; other fins all more or less 

 dusky; mouth dusky within. 



The Mission supplied two specimens, 555 and 605 mm. (490 and 

 548 mm. to base of caudal) long, both taken by trolling in the Gulf of 

 Guayaquil near Cabo Blanco, though not on the same date, one having 

 been caught on May 15 and the other one on August 15. The descrip- 

 tion is based on the two specimens from Peru, though I have had a 

 few from other localities for comparison. While this species is re- 

 garded as cosmopolitan, no one apparently has compared and studied 

 large series of specimens from different localities. It is possible, 

 therefore, that differences may yet be found. The Peruvian specimens 

 are plumper and have one less soft ray in the second dorsal and also 

 in the anal than in two somewhat smaller specimens from Florida, 



Although I follow Kishinouye (1923, pp. 452 and 457) in placing 

 this species in a different genus from the related skipjack (barrilete), 

 I am not sure that this can be done solely on the presence or absence 

 of palatine teeth. In both species, according to Peruvian specimens, 

 the palatine bones are bare, that is, there is a rift in the skin that covers 

 the roof of the mouth. In one specimen of E. alletterata, in which 

 the skin was cut away, I found some low protuberances on the bone, 

 which seem to be missing in Katsuwonus pelamis. The most obvious 

 distinguishing character, observable without dissection, is the great 

 difference in the number of giU rakers. In E. alletterata the body, 

 also, tapers more gently posteriorly, the pectoral fin is longer, and 

 dark spots (variable in number) are present below the pectoral fin. 



This species presumably is not numerous enough in Peruvian 

 waters to be of commercial value, and no distinctive local name was 

 supplied. 



Range. — A pelagic species of world-wide distribution in temperate 

 and tropical seas. No previous record of its occurrence in Peruvian 

 waters has come to my attention. 



Genus THUNNUS South, 1845 2» 

 Body moderately robust; snout pointed, not very long; mouth 

 rather large; maxillary not concealed by preorbital; teeth in jaws 



" This genus was divided into three genera by Kishinouye (1923, p. 433), namely, Thunnus South, Neo- 

 thunnus, new genus, and Parathunnus, new genus. The divisions were based entirely on internal (anatomi- 

 cal) characters. I do not follow this new classification for the same reason that I declined to follow the 

 splitting up of the family Scombridae as formerly understood (see footnote on p. 361). 



