234 On new Freshwater Fishes from South America. 



XXVI. — Descriptions of Three neio Freshwater Fishes from 

 South America^ presented to the British Museum hy Herr J. 

 Paul Arnold. By C. Tate Regan, M.A. 



1. Cichlosoma hiocellatum. 



Allied to C. coryphcenoides. Heck. Depth of body 2\ in 

 the length, length of head 2|. Snout a little longer than 

 eye, the diameter of ■which is 4 in the length of head ; inter- 

 orbital width 3 in the length of head. Fold of the lower lip 

 not continuous ; jaws equal anteriorly ; maxillary not quite 

 reaching the vertical from anterior edge of eye ; de|)th of 

 prseorbital nearly | the diameter of eye ; cheek with 6 series 

 of scales ; 8 gill-rakers on the lower part of the anterior arch. 

 31 scales in a longirudinal series, 5 in a transverse series 

 from origin of dorsal to lateral line, 4 between lateral line 

 and sheath at base of anterior part of soft dorsal. Dorsal 

 XIX 9; origin above opercular cleft ; spines subequal from 

 the seventh to the sixteenth^ thence increasing to the last, 

 whicli is ? the length of head; soft fin pointed, when laid 

 back reaching the middle of caudal. Anal VIII 8. Pectoral 

 shorter than the head, extending to above the third anal 

 spine. Caudal rounded. Caudal peduncle 3 as long as deep. 

 Body with 8 dark cross-bars ; third and fourth joined by an 

 oblong blackish spot, edged with whitish, below the lateral 

 line; in front of this a dark longitudinal band running 

 forward to the eye ; a blackish ocellus on the upper part of 

 the base of the caudal fin ; vertical fins with series of dark 

 spots. 



A single specimen, 80 mm. in total length, from i\Ianaos, 

 Rio Negro. 



C. coryphcenoides has XVI 12-14 dorsal and VI- VII 9-11 

 anal rays; the spines are longer and stronger than in C. hi- 

 ocellatum, from which it also differs in coloration and in the 

 form of the head. 



2. Otocinclus arnoldi. 



Depth of body 4^ in the length, length of head 31. Dia- 

 meter of eye 5^ in the length of head, interorbital width 2 ; 

 snout as long as postorbital part of head ; supraoccipital 

 without median ridge, strongly elevated posteriorly, its extre- 

 mity on the level of the origin of dorsal. Scutes not carinate, 

 •2r> m a -longitudinal series; abdomen with 3 longitudinal 

 series of plates. Dorsal I 7 ; origin above that of the pel vies ; 

 no adipose fin. Anal I 5. Pectoral spine extending beyond 



