43. CKENUOHTTS. 365 



Ninth Group. CRENUCHINA. 



Characinida with an adipose fin and with the dorsal rather 

 elongate, with the gill-membranes free from the isthmus, with 

 the belly rounded, and without canine teeth. 



South America. 



43. CRENUCHUS. 



Crenuchus, Giinth. Ann. fy Mag. Nat. Hist. 1863, xii. p. 443. 



Dorsal fin rather long, placed somewhat behind the middle of the 

 length of the body, above the space between <the ventrals and the 

 anal fin. Anal of moderate length. Caudal and adipose* fins with- 

 out scales. Body oblong, compressed, covered with scales of mode- 

 rate size ; lateral line none ; belly rounded. Cleft of the mouth 

 rather wide : intermaxillary and mandible with a single series of 

 small tricuspid teeth ; maxillary and palate without teeth. Nostrils 

 close together. Gill-openings wide, the gill-membranes not attached 

 to the isthmus ; gill-rakers elongate, lanceolate 



British Guiana. 



I. Crenuchus spilurus. 



Giinth. I. c 



D. 17. A. 11. V. 8. L. lat. 30. L. transv. 10 



Head and body much compressed ; the depth of the body is less 

 than the length of the head, which is contained thrice and one-third 

 in the total length, the caudal fin not included. The eye is situated 

 in the anterior half of the length of the head, its diameter being 

 equal to the extent of the snout, and to the width of the interorbital 

 space, which is one-fourth of the length of the head. The cleft of 

 the mouth is rather wide, the maxillary extending somewhat beyond 

 the vertical from the centre of the eye ; jaws equal in length ante- 

 riorly. The infraorbital bones are not much dilated, their greatest 

 width being equal to that of the orbit ; a great part of the cheek 

 remains naked. The dorsal fin commences a little nearer to the ex- 

 tremity of the snout than to the root of ^the caudal fin, somewhat in 

 front of the root of the ventral ; its last ray is opposite to the origin 

 of the anal fin ; the middle rays are as high as, or even higher than, 

 the body, equal in length to the longest anal rays. Caudal fin emar- 

 ginate ; pectoral rather small, not extending to the root of the ven- 

 tral ; ventrals longer than pectoral, reaching to the vent. 



Brownish, each scale with the margin darker. A round black 

 spot' on the end of the tail. Vertical fins black, with regular, round 

 white spots. 



Essequibo 



a. Two and a quarter inches long. Purchased of Mr. Ehrhardt. 



* In the original description the adipose fin, which is extremely small, has 

 been overlooked. 



