1906.] NATURAL SCIENCES OF PHILADELPHIA. 311 



evident. Preventral region keeled in similar manner to postdorsal, 

 only median keel most pronounced. Postventral and postanal region 

 keeled, former may be considered almost trenchant. Lateral line 

 continuous, of simple tubes, a little above middle in depth of body and 

 continuous to caudal. 



Dorsal high, third ray longest, and origin of fin would fall in vertical 

 about midway between tip of snout and base of adipose fin. Anal 

 small, anterior rays longest, margin of fin concave, and its origin 

 nearer base of caudal than origin of ventral. Adipose dorsal small, 

 its base inserted about opposite bases of last anal rays. Caudal long, 

 deeply emarginate and end of each lobe apparently more or less pointed. 

 Pectoral rather long, pointed, and extending beyond origin of dorsal 

 or about f of space to ventral. Ventral inserted nearl}' opposite middle 

 •of base of dorsal or about midway between origin of anal and that of 

 pectoral, and extending about | of distance to former, ^'ent close in 

 front of anal fin. 



Color in alcohol more or less pale brownish washed with silvery- 

 purplish. Back a little darker than side and lower surface. Body 

 also with about fifteen or rnore indistinct vertical or transverse purplish- 

 dusky bands. Dorsal with about six series of brownish spots on rays. 

 Other fins pale plain brownish. Iris brassy. 



Length 5 inches. 



Type, No. 8,207, A. N. S. P. Parahyba, Brazil. jMuseum of Com- 

 parative Zoology, Cambridge, Mass. Only one example, the type. 



This species is closely related to Prochilodus corimhata (Kner) = 

 Salmo corimhata -Natterer, in Kner = P. nigricans Kner, nee Agassiz = 

 P. oligolepis Giinther. Dr. Steindachner's account of the last does 

 not give the coloration. Other related species are P. hiimeralis 

 Giinther and P. vimboides Kner, both differing in proportions, etc. 



(Named for Dr. Franz Steindachner.) 



Subgenus PROCHILODUS Agassiz. 



Scales small, more than 40 or usually between 40 and 60 in a lateral 

 count. Mouth similar to that of Chilomyzon. 



Prochilodus ortonianus Cope. Fig. 12. 



Proc. Amer. Philos. Soc. Phila., XVII, 1S77-7S (May 17, 1878), p. 685. No. 

 21,267 (type), A. N. S. P., cotype. Nauta, Peru. Prof. J. Ortou. Coll, 

 of 1873. 



Width of head 1§ in its length ; width of mouth 2f ; interorbital space 2. 

 Body robust, compressed, and caudal peduncle similar. Head broad, 

 robust, convex on upper surface, and lower surface but little restricted 



