144 CALIFORNIA ACADEMY OF SCIENCES. 



and microcephala have the dorsal placed over the ven- 

 trals. 



103. Heptapterus mustelinus. 



Pimelodas mnsteliniis Valenciennes, Orbigny, Voy. Amer. Merid. 



Poiss. pi. 2, fig. 1-4, 1847; Cuv. & Val. Hist. Nat. Poiss. xv, 



165, 1840 (La Plata); Hensel, Wiegm. Arch. 1870, i, 77 (St. Cruz, 



Rio Grande do Sul). 

 Heptapterus mustelinus Giinther, Cat. Fish. Brit. Mus. v, 271, 1864 



(copied); Eigenm. & Eigeum. Proc. Cal. Acad. 2d Ser. i, 172, 



1888 (Maldonado). 

 Habitat: Eio Grande do Sul; Eio Plata. 



Caudal portion compressed, the abdominal portion 

 very little depressed. Head depressed, its depth Ih in 

 its width, entirely covered with smooth skin. 



Eye an orbital diameter nearer tip of snout than to 

 the gill opening. 



Maxillary barbels reaching to middle of pectoral fins, 

 the mental and postmental barbels to the edge of gill- 

 opening. Width of mouth 2 in length of head, the 

 gape about 2 in the snout. Teeth villiform in both jaws. 



Gill-membranes separate to below the eye. 



Distance of dorsal fin from tip of snout 2| in the 

 length, the first ray not stiffened. Adipose fin very long 

 and rather low, originating a little nearer the dorsal fin 

 than the length of the latter, continuous with the cau- 

 dal fin. 



Caudal fin rounded, its accessory rays continued for- 

 ward below to the anal fin, but wholly free from it, 

 anterior portion scarcely rayed, adipose-like. 



Anal long and low, inserted a little posterior to the 

 adipose fin. 



Ventrals inserted a very little posterior to the origin 

 of the dorsal fin, reaching about half way to the anal, 

 the pectoral fins not quite so near to the ventrals. 



Color uniform grayish, everywhere dotted with dark 

 except on the belly; fins also punctate, the anal and ven- 

 trals least so. 



