164 CALIFORNIA ACADEMY OF SCIENCES. 



edentulous. Fontanel not extending backward beyond 

 the eyes. Humeral process broad, not spine-like. Crown 

 of head granulose; in one species covered by very thin 

 skin. Dorsal I, 6. Dorsal and pectoral spines stout. 



DOUBTFUL SPECIES OF PIMELODUS. 



119.1. Rhamdia cyanostigma Cope, Proc. Am. Philos. 

 Soc. 11, 569, 1870 (Pebas, Ecuador). 



We are unable to tell to which genus this species be- 

 longs. Dr. Cope says (Proc. Am. Philos, Soc. 1878, 

 675), that this species is allied to Pimelodus ophthalmicus 

 =zPimelodella cristatus. But cristatus is generically dif- 

 ferent from Rhamdia, and was generally considered so 

 when the statement was made. 



Top of head smooth or with a slight rugosity on the 

 postfrontal region. Depressed dorsal not reaching adi- 

 pose fin. Pectoral reaching f to ventral, ventrals h, to 

 anal. Caudal deeply forked, the lobes equal. Maxillary 

 barbels reaching to near the end of the adipose fin. 

 Color plumbeous; head above blackish, with an irrides- 

 cent blue spot above the posterior margin of the orbit 

 on each side. 



Head less than 5 in the length; depth 73-; adipose fin 

 3J; D. I, 6; A. 12. 



119.2. Silurits quadrimaculafus Bloch, Ausland. 

 Fische, part 8, 37, plate 368, 1794 (America); Cuv. & 

 Val. Hist. Nat. Poiss. xv, 185, 1840 (America). 



Adipose fin long, covering almost the entire postdor- 

 sal region. Head flat, opercles granular. Palate rough. 

 Maxillary barbels as long as the entire fish. Vent equi- 

 distant from snout and caudal. Only the pectoral spine 

 stiff, and with teeth. Body brown with violet reflec- 

 tions, ashy below, fins yellowish. Br. 5; D. 7; A. 9. 



Bloch says nothing in his description about the four 

 fantastical spots of his figure. Perhaps the spots were 

 placed there to have the fish agree with its name. 



