664 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



The differences between the males and females are as follows: 

 J/ale. — a. Maxillary barbel erectile, spinous, with 5 or 6 accessory 

 spines on its anterior surface; profile very strongly concave; a bulge 

 on the anterior surface near dorsal l)ase; dorsal more or less crooked; 

 equal or greater in height than its distance from the tip of the snout; 

 its anterior margin spinulous, hooks more or less regularly turned to 

 the right or left; posterior surface of dorsal spine smooth. Pectoral 

 spine a little longer than snout and eye, nearly smooth in front and 

 with recurved hooks behind. Eye 3 in snout, 6 in head, 3 in inter- 

 orbital. Caudal margined with black. One of the males everywhere 

 much darker than the other. (Two specimens.) 



Female. — ((a. Maxillary barbel minute, its base cartilaginous, its tip 

 not reaching to the end of the premaxillar}" by a distance equal to the 

 diameter of the pupil. Dorsal spine feeble, not as long as the first 

 ray, its length contained a little more than twice in its distance from 

 the tip of the snout. Pectoral spine slender, smooth in front, with 

 recurved teeth behind; about ecj[ual in length to snout and orbit. £3^6 

 3i to 4 in snout; 6i in head; 3f in interorbital. Caudal not margined 

 with black. Profile but little concave. (Three specimens,) 



HYPOPHTHALMUS EDENTATUS Spix. 



One specimen. 



HEMICETOPSIS CANDIRU (Spix). 



One specimen, a male, agreeing with the description of Eigenmann 

 and Eigenmann except in the chai"acter of the dorsal and pectorals. The 



Fig. 3. — Paeacetopsis occidentalis. (After Steindachner.i 



first ray of each of these is prolonged. The first dorsal ray is 2^ times 

 as long as second, being prolonged with a filament. The first pectoral 

 ray is similarly prolonged, being about twice the length of the second 

 ray and reaching to the vcntrals. 



