210 



PROCEEDINGS OF THE ACADEMY OF 



[Apr., 



broadly depressed. Fontanel moderate, not extending back beyond 

 hind eye edges. Occipital process extends only for first fourth in 

 space to dorsal origin. Humeral process smooth, extends f length 

 of pectoral spine. Opercle broadly triangular, with a few shght 

 radiating striae. 



Gill-opening extends forward about first third in head. Rakers 

 3+8, firm, lanceolate, simple, about i of filaments, and latter equal 

 eye. No pseudobranchise. Branchiostegals 6, slender. 



Body covered with smooth skin. Head smooth. Spines smooth. 

 L. 1. slopes down from shoulder till midway along side. Axillary 

 pore moderate. 



Dorsal origin shghtly nearer anal origin than snout tip, spine short, 

 slightly curved, smooth and pungent, and first three rays subequally 

 longest. Anal inserted nearly midway between depressed pectoral 



Fig. 2. — Rhamdia riojce Fowler. (Type.) 



tip and caudal base, fin small, and median rays longest. Adipose 

 dorsal long, its length about 2f in combined head and trunk length. 

 Caudal moderately forked, lobes (damaged) apparently equal, and 

 length about f of head. Pectoral not quite half way to ventral, 

 spine firm, smooth, outer edge with few weak antrorse serrse ter- 

 minally, and few obsolete serrse also on inner edge. Ventral inserted 

 about midway between snout tip and caudal base, fin If to anal 

 origin. Vent about opposite middle of depressed ventrals. 



Color in alcohol largely dark brown, belly and lower surface of 

 head paler or whitish. Fins all dusky-brown, though ventrals and 

 anal paler. Iris brownish. Barbels pale bro-wiiish. 



Length 184 mm. 



Type, No. 21,101, A. N. S. P. Rioja, near Moyabamba and Baka 



