Z2 FISHES FROM BRAZIL 



or naked; the humeral process is shorter and does not project so much later- 

 ally at the base over the base of the pectoral spine ; no pectoral pore is 

 present ; the top of the head between the eyes in the adult is a little flatter ; 

 and in the specimens at hand the color is darker and the under parts dusky 

 with fine points. These differ from the original description in having 2 or 

 3 fewer anal rays. 



103. Pseudauchenipterus nodosus (Bloch). 



A number of specimens from 6 to 9 inches in length were taken at 

 Para, which I refer, with considerable hesitation, to this species, though 

 they agree very well with the picture* and short description of Pseudau- 

 chenipterus guppyi Regan (Proc. Zool. Soc. 1906, PI. XXIII). The head 

 cannot be described as having the "upper surface, excepting the snout, 

 rugose, not covered by skin; frontal bones not swollen." On the contrary, 

 the top of the head is as described by Dr. Eigenmann (S. Am. Nematog- 

 nathi, p. 290) for P. nodosus, with the f rentals swollen and of distinctly 

 "honey-comb structure." It is covered with thin skin. These specimens 

 have the color markings as described and figured for P. guppyi, with the 

 same light lateral band and vertical row of light spots, and with or without 

 the black border to the caudal. These markings are occasionally obscure, 

 though they are usually very conspicuous. They differ from Dr. Eigen- 

 mann's description of P. nodosus as follows : The pectoral spine is usually 

 sharp-pointed and does not end in a filament. Its length is from 4 to 4^ 

 (not from 2^ to 3}^) , thus agreeing with the pictures published by Bloch 

 and by Bleeker. The humeral process usually extends to the middle of the 

 pectoral spine or a trifle beyond. 



104. Auchenipterus nuchalis (Spix). 



Very common at Para, where a large number were collected. 



There is a remarkable variation in the maxillary barbel. In most of 

 them the barbel extends straight back under the eye. It is very slender, its 

 anterior end ossified, and it fits into a shallow groove immediately below the 

 eye. In the opposite extreme the base of the barbel is a wide curved bone, 

 much wider than the pectoral spine, and its curve forms at least a fifth of 

 a complete circle (though it is not an even curve, being more abrupt below 

 the eye). It extends upward from the eye, and ends above the level of the 

 eye a little behind the head. It does not taper much posteriorly, but ends 



* The title of the picture and the reference in the text are transposed with those 

 of P. pasecE. 



