344 



MEMOIRS OF THE CARNEGIE MUSEUM. 



gill-opening which is restricted to the space behind the interopercular spines, the 

 membrane being confluent with the shoulder behind the opercular spines; mouth 



sub terminal, a single series of teeth in each jaw, about 

 sixteen on the pre-opercle and about thirteen on the 

 mandible. The teeth of the two jaws alike, similar to 

 the teeth at the end of the premaxillary of Branchioica and 

 some species of Vandellia. They consist of a narrow 

 basal section, an enlarged middle section, from the inner 

 (median) angle of which projects a short spur laterad, the 

 spur being slightly twisted from the plane of the rest of 

 the tooth; the teeth not movable; interopercle with a 

 single series of six backward directed, slightly divergent 

 spines; opercular spines slightly divergent, four spines 

 in the main posterior row; five much smaller ones in 

 the anterior row; caudal forked. 



Pareiodon has the appearance of an overgrown Van- 

 dellia, from which it differs in dentition, in the size of the 

 eye, and the general shape of the head. 





Fig. 21. Pareiodon microps 



Kner. a, outline of head from 

 above; b, the interopercular 

 spines; c, the opercular spines; 

 d, a premaxillary and a man- 

 dibular tooth, very much en- 

 larged. 



1. Pareiodon microps Kner. (Plate LIV, fig. 3.) 



Pareiodon microps Kner, /. c. (Borba on the Madeira about four days from its 

 mouth); Eigenmann & Eigenmann, Proc. Cal. Acad. Sci. (2), II, 1889, 

 p. 55; Occasional Papers Cal. Acad. Sci., I, 1890, p. 346; Proc. U. S. Nat. Mus., 

 XIV, 1891, p. 37; Ribeiro, Fauna Bras., IV (A), 1912, p. 232; Comm. Linhas 

 Telegraphicas Estratcgicas de Matto-Grosso ao Amazonas. Annexo 5, Sept., 

 1912, p. 30 (Manaos) ; Fowler, Proc. Acad. Nat. Sci. Phila., 1915, 229 (Amazon 

 between mouth of Rio Negro and Peru). 



Pariodon microps Gunther, Cat. Fishes Brit. Mus., V, 1864, p. 275; Cope, Proc. 

 Acad. Nat. Sci. Phila., 1872, 290 (between Rio Negro and Peru.) 



Trichomycterus pusillus Castelnau, Anim. Amer. du Sud, Poissons, 1855, p. .50, 

 pi. 24, fig. 4 (Araguay; Amazon). 



Astcmomycteriis pusillus Guichenot, I. c. (Araguay; Amazon). 



Pareiodon pusillus Ribeiro, I. c., p. 234. 

 Habitat. — Amazon Basin. 

 The specimen in the collection of the Philadelphia Academy of Sciences, 



mentioned by Cope and Fowler, is about 145 mm. long. I am indebted to Dr. 



Fowler for the loan of this specimen. 



