146 CALIFORNIA ACADEMY OF SCIENCES. 



of the head; each jaw with a band of strong villiform 

 teeth. 



Origin of dorsal fin from tip of snout 3j in the length. 



Adipose fin long and low, its origin in advance of the 

 anal, confluent with the caudal fin. Caudal with num- 

 erous accessory rays, widely forked, its upper lobe longer, 

 about 5| in the length. Origin of anal a little nearer 

 base of caudal than to gill opening, the rays of about 

 equal height. Ventrals high and narrow, inserted be- 

 low the first dorsal ray. Pectorals long and narrow, 

 scarcely shorter than the head, the middle rays longest. 



Brownish, with traces of a dark lateral band; a dark 

 bar extending forward from the eye; two dark lines on 

 base of caudal and parallel with its root. 



Head 7^; depth 10; D. 7; A. 19. 



105. Acentronichthys surinamensis. 



Heptapterus suriiiamensis Bleeker, Siliires de Suriname, 91, pi. xv, 

 fig. 1, 1864 (Surinam); Gtinther, Cat. Fish. Brit. Mus. v, 271, 

 1864 (copied). 



Habitat: Surinam. 



This species is known from the types only. 



106. Acentronichthys collettii. 



Heptapterus collettU Steindachner, Flussfisclie Siidam. iii, 7, pi. v. 



fig. 1, 1881 (Maldouado). 

 Habitat: Mouth of the Eio Plata in brackish water. 



This species is known from the types only. 



XIX. Nannoglanis. 



Nannoglanis Boulenger, Proc. Zool. Soc. Lond. 278, 

 1887 (fasciatus). 



A. 8. Adipose fin present; dorsal fin without a pun- 

 gent spine and placed behind the ventrals. Barbels six; 

 Fontanel ? Occipital process ? 



We have not seen the only known species of this ge- 

 nus but its general structure is so much like that of 

 Heptapterus and Rltamdella that we think we are war- 



