274 PROCEEDINGS OF THE ACADEMY OF [Apr., 



Only the type known. 



(AtoTzapSwi^ leopard; with reference to the spots.) 



Plecostomus plecostomus (Linnaeus). 



One example, 235 mm. 



Pseudancistrus nigrescens Eigenmann. 



Two examples, 112 and 175 mm. The smaller example agrees 

 Avith Eigenmann's figure of the head, though the larger has the 

 posterior edge of the occipital plate triangular. Both have numerous 

 lateral bristles around front edge of head, except about snout tip, 

 though in the larger example they are much longer, slender, and 

 altogether better developed. Mandibular ramus IJ to If in inter- 

 orbital. Dorsal spine equals or less than combined eye and snout 

 length. Pectoral extends back about opposite first third in ventral. 

 Color uniform dark brown above, belly pale. Trunk with brassy 

 tinge in places. 



Ancistrus hoplogenys (Gtinther). 



Two examples, 120 and 178 mm. Both show body, especially 

 below, and fins with minute white spots. 



LORICARIIN^. 



Loricariichthys acutus (Valenciennes). 



One example, 210 mm. long (caudal tip damaged). This species 

 has been described by Eigenmann as Loricaria microdon. My 

 example does not appear to differ from L. acutus as described by 

 Regan. 



Loricariichthys griseus (Eigenmann). 



One example 167 mm. 



Harttia platy stoma (Gunther). 



One example 145 mm. 

 Sturisoma monopelte sp. nov. Fig. 18. ^ 



Head 5|; depth 9|; D. I, 7; A. I, 5; P. I, 6; V. I, 5; osseous 

 plates 35 in lateral series; 24 postdorsal bony plates; head width 

 If in its length, measured to hind edge of occipital process; head 

 depth 3; snout If; eye 6|; mouth-width 4; interorbital 4|; snout 

 tip to front mouth edge 2j; pectoral If; ventral If; anal 1^; least 

 width of caudal peduncle 6|. 



Body greatly elongate and depressed, slender in profile, dorsal 

 and ventral surfaces generally convex. Very slight median predorsal 

 depression, with slight ridge each side. From upper edge of eye 

 obsolete keel extends back to join median lateral keel at fifteenth 



