SOUTH AMERICAN NEMATOGNATHI. 195 



Habitat: Rio Parahyba to Guiana; Amazon to Cal- 

 deron. 



The group of long and spatulate Pimelodinse of 

 Gunther can scracely be retained, because perfect inter- 

 gradations exist, and because some of the short-snouted 

 genera Piratinga, Piramutana have really longer snouts 

 than Steindachneria, Duopalatinus, and Brachyplatystoma. 



ANALYSIS OF THE SPECIES OF BRACHYPLATYSTOMA.* 



a. Maxillary barbels reaching past base of ventrals. 



b. Skin not entirely reticulate; occipital process long, reaching to the 



dorsal plate or slighty shorter. vaillanti 143. 



bb. Skin everywhere reticulate; occipital process not reaching to the 



dorsal plate; longest caudal ray almost as long as the head. Head 4; 



Br. 12; D. I, 6; A. 12. (Kner.) reticulatum 144. 



fia. Maxillary barbels not extending to the ventrals. rousseauxii 145. 



142. Brachyplatystoma filamentosum = vaillanti ? 



Pimelodes filamentosus Lichtenstein, Wiedem. Zool. Mag. i, part 3, 



60 (Brazil). 

 Malacobagrus Jilamentosus Bleeker, Nederl. Tijdschr. Dierkunde, i, 



1863, 100 (name only). 

 Piratinga filamentosa Giiiither, Cat. Fish. Brit. Mus. v, 112, 1864 



(copied). 

 Brachyplatystoma filamentosum Eigenm. &Eigenm. Proc. Cal. Acad. 



2d Ser. vol. i, 1888, 136 (name). 

 Habitat: Brazil. 



This species is a true Brachyplatystoma with the teeth 

 as described for this genus. It cannot be separated on 

 account of the number of branchiostegal rays because 

 Lichtenstein states that they cannot be counted, and he 

 estimates them at 7. 



Br. 7; D. 7; A. 9. Upper caudal lobe produced; length 

 to end of lower caudal lobe 9 inches, to end of upper 

 caudal lobe 22 inches. 



Maxillary barbels 24 inches. Spine soft. Head flat- 

 tened forward, pointed. Occipital process scarcely 

 noticeable, 1 inch from the dorsal spine. Adipose fin as 

 long as and opposite to the anal. Upper jaw longer, 



*142. Bracfiyplatystoma filamentosum is left out of this key. 



