214 PROCEEDINGS OF THE ACADEMY OF [Apr., 



Pimelodus maculatus Lac6pede. 



Pseudorhwndia piscalrix Cope, Proc. Amer. Philos. Soc, XI, 1870, p. 569. 

 Pebas, Ecuador. 



No. 8,387, A. N. S. P., type of P. piscatrix Cope. Pebas, Ecuador. 

 J. Hauxwell. 



Also examples from Demarara, Surinam, Ambyiacu River, and 

 between the mouth of the Rio Negro and the Peruvian Amazon. 



Pimelodus valenciennis Liitken. 



Rio Jacuhy, Brazil. 



Pimelodella cristata (Muller and Troschel). 



Pimelodus ophthalmicus Cope, Proc. Amer. Philos. Soc, XVII, 1878, p. 675. 

 Peruvian Amazon. 



No. 21,102, A. N. S. P., cotypes of P. ophthalmicus Cope. Peru- 

 vian Amazon. J. Orton. 1873. Presented by E. D. Cope. 



Pimelodella peruense sp. nov. Fig. 4. 



Head 4i; depth 4f ; D. I, 6; A. v, 9; P. I, 11; V. i, 6; head 

 width 1| in its length; head depth at occiput 1|; snout 3; eye 3^; 

 maxillary about 4; interorbital 3|; dorsal spine 2; second branched 

 dorsal ray IJ; least depth of caudal peduncle 2i; pectoral fin 1^; 

 ventral If. 



Body compressed, moderately elongate, somewhat slender, deepest 

 at dorsal origin, and edges all convex. Caudal peduncle well com- 

 pressed, and length about f its least depth. 



Head about wide as deep at occiput, sides convexly approximated 

 above and broad or somewhat flattened below. Snout convex over 

 surface, length about half its greatest width. Eye large, near 

 upper profile, and about midway in head length. Eyelids little 

 free, not adipose-like. Mouth broad, transverse, and upper jaw 

 slightly protrudes. Teeth fine, villiform, in rather broad contigTious 

 bands in jaws. No vomerine or palatine teeth. Tongue broad, 

 thick, depressed, not free. Maxillary barbel reaches origin of 

 ventral. Outer mental barbel extends about first eighth in da- 

 pressed pectoral, and inner mental barbel about f to pectoral origin. 

 Posterior internasal area slightly greater than anterior, and anterior 

 nostrils in short tubes, posterior simple pores. Interorbital slightly 

 convex. Fontanel large, continued to base of occipital process 

 without interruption. Humeral process f length of depressed 

 pectoral spine. Occipital process elongate, slender, extends f to 

 dorsal plate. Opercle broad, smooth. 



Gill-opening extends forward opposite front pupil edge. Rakers 

 3 + 8, firm, lanceolate, simple, little less than half of filaments, 



