SOUTH AMERICAN NEMATOGNATHI. 191 



b. Eye large, 6 in head; maxillary barbels exteudiug beyond dorsal, be- 

 yond caudal in young. Vomerine teeth in two patches which be- 

 come united in the adult. pictus 139. 



aa. Surface of the head and occipital process eutirel}' covered with thick 

 skin, outline of occipital process entirely hidden iiuder the skin; head 

 little longer than broad. (Sciadeoide.s.) 



c. Eye 10 in head; maxillary barbels extending to the end of the adipose 

 fin. Vomerine teeth alM^ays in two ijatches. marmoratus 140. 



139. Sciades pictus. 



Bagrus (Sciades) pictus Miiller & Troschel, Horas Ichthyol. iii, 8, 



1849; Kner, SB. Ak. Wien, xxvi, 386. 

 Sciades pictus Giinther, Cat. Fish. Brit. Miis. v, 113, 1864 (copied); 



Eigeum. & Eigenm. Proc. Cal. Acad. •2d Ser. i, 136, 1888 (Rio 



Negro; Villa Bella). 

 Arius {?) longibarhis Castlenau, Anim. Nouv. Eares de I'Amerique 



du Sud, 36, plate xv, fig. 2, 1855 (Amazon). 

 Sciades loiigibarbis Giinther, Cat. Fish. Brit. Mus. v, 114, 1864 



(copied). 

 Habitat: Amazon and its tributaries. 



The description and figure of pictus agree with a 

 specimen .28 m. long in all characters except the vom- 

 erine teeth, which are in two separate patches. Miiller 

 & Troschel doubtless overlooked the narrow interspace 

 between the vomerine patches, as Castelnau overlooked 

 the palatine teeth. There can be no doubt but that 

 pictus M. & T. and longibarhis Castelnau are identical. 



A specimen .28 m. long was collected by Prof. Agassiz 

 at Villa Bella, another .60 m. long was collected by Mr. 

 Dexter in the Rio Negro. 



Head narrow angular, flattish above, its width at the 

 rictus If in greatest width, which is equal to 1^ in 

 length of head; Fontanel not continued behind the 

 frontals. Body rather deep at the dorsal fin. 



Eye 2^-2f in snout, 5-6 in head, 2-2^ in interorbital. 



Maxillary barbels extending beyond tips of caudal in 

 specimens .28 m. long, little beyond dorsal in specimens 

 .60 m. long; mental barbels to base of pectorals or be- 

 yond; postmentals beyond base of ventrals (.28) or to 

 middle of pectoral (.60 m.) 



