306 PROCEEDINGS OF THE ACADEMY OF [June, 



approach caudal. In alcohol brassy-brown with more or less silvery. 

 Back till about level with occiput a dull olive-brown. Upper surface 

 of head brownish. Body mostly washed with silvery. Fins plain 

 brown, and pale like side. Iris brown. Length 5^ inches. This is the 

 largest example. It is from between the mouth of the Rio Negro and 

 the Peruvian Amazon. Robert Perkins. Also another example with 

 same data. These are labelled, evidently in Cope's handwriting, as 

 "Curimatus cyprinoides v. ajf." 



Besides the above are 5 examples from the Ambyiacu river in the 

 Hauxwell collection. Cope's label reads ' ' Curimatus rutiloides. ' ' An 

 examination of the air-vessels of two of these examples shows that it 

 persists nearly as far posteriorly till opposite base of penultimate anal 

 ray. It is thus apparent that Cope may have intended all the ex- 

 amples before me to represent his C. rutiloides, but the original labels 

 in his own handwriting would lead to the above allocating of the 

 references. The form called Psedrogaster amazonica by Dr. and Mrs. 

 Eigenmann I cannot distinguish in my examples. 



Potamorhina pristigaster (Steindachner). 



Cope, Proc. Amer. Philos. Soc. Phila., XVII, 1877-78 (May 17, 1878), p. 685. 

 Peruvian Amazon, probably from Nauta. Prof. J. Orton. Coll. of 1873. 



Head 3; depth 2 to 2^, a little larger in smaller specimen; D. iii, 9; 

 A. Ill, 11 to III, 13, i; ventral scutes 22 to 28; scales (squamation 

 damaged) about 90 in lateral line to base of caudal and several more 

 on latter ; snout 3^ to 3f in head ; eye 4|- to 4| ; width of mouth 3^ 

 to 3-^ ; interorbital space 2^ to 2f ; total length of 3 examples 6 to 9 

 inches (caudal damaged). 



Anodus elongatus Agassiz. Fig. 9. 



Anodus steatops Cope, Proc. Amer. Philos. Soc. Phila., XVII, 1877-78 (Mav 

 17, 1878), p. 683. Nos. 21,498 (type) and 21,499, A. N. S. P., cotypes. 

 Pebas. Prof. J. Orton. Coll. of 1877. 



Body rather plump. Head broadly convex above, a little restricted 

 below. Snout when viewed above rather rounded. Edges of jaws 

 not sharp. Lips thin. Rami of mandible well elevated inside mouth. 

 Tongue large, elongate, flattened above, rounded in front and free. 

 Inside mouth upper membrane broad. Interorbital space broadly 

 convex. Gill-opening extending forward to front margin of orbit. 

 Rakers 66? + 100?, long, slender, or very fine and numerous and long- 

 est equal to 1|- eye-diameters. On inner edge of first branchial arch 

 also a series shorter in length. Longest filaments nearly equal orbit. 

 Isthmus long, narrow and slender. A triangular naked space extend- 

 ing back on occiput. Edges of body rounded except those of lateral 



