128 BULLETIN 189, UNITED STATES NATIONAL MUSEUM 



ing its length; origin of dorsal full length of snout behind base of 

 pectoral spine, distance anterior to origin of dorsal 2.5 to 2.75 in length; 

 dorsal spine long, slender, rough on anterior margin, posterior margin 

 with small barbs, not extending to tip of soft rays, 1.15 (in adults) 

 to 2.0 (in young) in head; adipose fin moderately large, its origin over 

 about the beginning of the second third of anal, its base 2.25 to 3.0 

 in head; caudal moderately forked, the upper lobe longer and nar- 

 rower than the lower; anal with slightly concave margin in adult, 

 rounded in young, its base 1.25 to 1.33 in head; ventral rather small, 

 not quite reaching origin of anal, inserted rather nearer base of pec- 

 toral spine than middle of base of anal; pectoral failing to reach 

 ventral by about diameter of eye, the spine rough on outer margin, 

 with small barbs on inner margin 1.3 to 1.75 in head. 



Color dark blue above, becoming silvery on lower part of side, and 

 pale silvery underneath; fins mostly pale with dusky punctulations. 



Figure 28. — Arius multiradiatus Giinther. From the type of Tackysurus equatorialis 

 Starks, 193 mm. long, Guayaquil, Ecuador (U.S.N.M. No. 53470). (After Starks, 1906.) 



The Mission obtained 3 specimens, 57, 58, and 147 mm. (46, 46, 

 and 117 mm. to base of caudal) long, all from the Gulf of Guayaquil, 

 off Puerto Pizarro. One of the specimens (U.S.N.M. No. 77596), 185 

 mm. long, obtained by R. E. Coker at Paita, upon which the account 

 by Evermann and Radcliffe (1917, p. 32) of Tachysurus equatorialis 

 was based, also is at hand. The foregoing description is based on the 

 four specimens listed. These were compared with specimens from 

 Panama, identified as A. multiradiatus, and with the type (U.S.N.M. 

 No. 53470) of Tachysurus equatorialis with which they agree perfectly. 

 Fowler (1941a, p. 370) apparently mistakenly synonymized T. equa- 

 torialis Starks with Arius furthii Steindachner. The last-mentioned 

 species was originally described from "Panama" (presumably meaning 

 Panama City). The number of anal rays was given as 20 to 22. 

 Specimens from Panama Bay, having that number of anal rays, also 

 have fewer gill rakers (9 to 11 on lower limb of first arch), and the 

 palatine teeth are blunter and in larger patches, therefore represent- 

 ing a different species. 



Range. — Panama Bay to Paita, Peru. 



