THE CATFISOHES OF VENEZUELA — SCHULTZ 187 



11a. Base of each lobe of caudal fin with embedded black pig- 

 ment spot, this pair visible at all ages; bases of anterior 

 pair of mental barbels much in front of bases of posterior 

 pair; margin of ej-e free dorsally, more or less fused 

 ventrally ; posterior pair of nasal openings closer to anterior 

 ones than to eye; underside of snout flat, in same plane as 



underside of head and belly Megalonema Eigenmann 



116. No pair of embedded pigment spots in caudal region; bases 

 of mental barbels in a straight line or nearly so; margin 

 of eye not free; posterior nasal openings closer to eye 

 than to anterior nasal openings; underside of head 

 convex; usually a pale saddle across occiput. 



Cetopsorhamdia Eigenmann and Fisher 

 106. Postcleithral process represented by a very small spine oflf 

 upper posterior base of pectoral fin; pectoral spine weakly 

 pungent; dorsal margin of eye free in well-preserved speci- 

 mens, otherwise the margin dorsally and ventrally appear- 

 ing fused; posterior nostrils much closer to eye than to 

 anterior nasal opening; bases of mental barbels in a straight 



line or nearly so Nannorhamdia Regan 



2b. Prominent and distinct paired patches or bilaterally symmetrical patches 



or bands of teeth in roof of mouth behind premaxillary band of teeth; 



dentaries with a band of teeth; teeth more or less conical, villiform,Fome- 



times depressible; head broad, depressed anteriorly, snout sometimes 



produced, spatula-shaped; margin of eye free; nostrils widely separated, 



the posterior one always much closer to anterior nasal opening than to eye; 



inner edge of operculum with one or two folds of skin or "pouches", 



dorsal rays I, 6 to I, 10. (See fig. 3.) 



12a. Upper jaw shorter than lower jaw, latter projecting a little beyond tip of 



snout; inner or anterior mental barbels near tip of chin or lower hp; 



maxillary barbels not extending beyond base of adipose fin; adipose fin 



longer than anal fin base; patches of villiform teeth in upper surfaces of 



mouth; dorsal rays I, 6; anal v, 8; pectoral I, 9. 



Hemisorubim Bleeker 

 126. Upper jaw equal to or longer than lower jaw; bases of mental barbels 

 remote from edge of lower lip. 

 13a. Upper jaw and lower jaw equal; maxillary barbels bandlike, extend- 

 ing to middle of pectorals; caudal forked; vomerine patch of teeth 

 broad at sides; no teeth on palatines; dorsal ra3^s I, 6; anal 16; 



pectoral I, 9 Platynematichthys Bleeker 



136. liOwer jaw distinctly shorter than upper jaw when closed. 



14a. Upper jaw or snout greatly prolonged, flattish, with teeth on under- 

 side of snout, mostly in front of lower jaw; dorsal rays I, 6. 

 15a. Eyes lateral so that they can be seen from above or below; band 

 of premaxillary teeth, mostly on underside of snout, horseshoe- 

 shaped; patches of teeth in roof of mouth; maxillary barbel 

 not reaching past dorsal fin; distance across angles of mouth 

 about equal to widest part of head; adipose fin shorter than 

 anal fin; anal v, 14; pectoral I, 8. (Fig. 3, h.) 



Sorubim Agassiz 

 156. Eyes superior, not visible from below. 



16a. Patch of premaxillary teeth arrow-shaped; adipose fin longer 

 than anal fin base; vomer and palatine patches of teeth 

 widely separated; first half of maxillary barbel ossified and 



