312 



PROCEEDINGS OF THE ACADEMY OF 



[June^ 



though more evenly convex. Width of head more or less even. 

 Snout broad, convex above and broadly rounded when viewed from 

 above. Interorbital space convex and median narrow fontanel extend- 

 ing from internasal space to occiput. Head with arborescent mucous 

 canals on upper side posteriorly and on suborbital region. Gill-open- 

 ing falling a trifle short of posterior margin of orbit. Rakers none. 

 Gill-filaments about 1^ in eye. Isthmus broad. Branchiostegals 4, 

 large, well developed and subequal. Scales a little rough and each one 



Fig. 12. — Prochilodus ortonianus Cope. 



with several striae. Predorsal region slightly keeled. Postdorsal 

 region rounded. Upper and lower surfaces of caudal peduncle a 

 little flattened. Preventral region flattened medianly. Postventral 

 region sharply keeled medianly and an obsolete keel on each side, all 

 three converging towards vent. Color in alcohol at present dull 

 olivaceous or brassy-brown, back with more or less dull metallic 

 shades. Fins all pale brownish, dorsal and caudal each with about 8 

 series of brownish spots on each ray of former, and about 6 on each 

 lobe of caudal, so that on latter they form more or less transverse 

 bands. Iris brownish. Length 7| inches. Type. 



Prochilodus cephalotes Cope. Fig. 13. 



Proc. Amer. Philos. Soc. Phila., XVII, 1877-78 (May 17, 1878), p. 686. No. 

 21,211, A. N. S. P., type. Peruvian Amazon. Prof. J. Orton. Coll. of 

 1873. 



Width of head If in its length; width of mouth 2^; interorbital space 



