THE CORVINA OP THE ESSEQUIBO. 137 



is tied up near their haunts. The colour is of a 

 silvery blue ; the dorsal and anal fins spotted Avith 

 black ; the scaling of moderate size, fringed, and 

 adhesive ; lateral line straight and near the middle 

 of the body ; head depressed ; ventral fins a little 

 behind the pectoral. Nostrils double, and situate 

 near the eye; eyes oval wHith the iris red; the 

 mouth terminal, jaws nearly equal; teeth fine, in 

 single row^s in both jaws ; gill-covering scaled, and 

 smooth at the edges. Feeds on insects and small 

 fish, and is generally found among the rapids." 



In some of the species the air-bladder is described 

 as fringed with numerous appendices ; in others, such 

 as C. oscula^ Yah, it is quite simple, and very large. 

 The stomach of this fish presented pyloric appendices, 

 and was filled with the debris of fresh-water shells. 

 In the C. ni^rita, Val., the air-bladder is large and 

 lengthened to a narrow point ; on each side of the 

 anterior part, there arises a small short process, 

 which divides into five branches ; from the two in- 

 terior of these spring two very short branches; 

 while the three others, equally divided, are prolonged 

 into lengthened filaments, which are retained by a 

 fatty cellular tissue upon the sides of the bladder. 



D. 9/32— P. 14— V. 6— A. 1/7— C. 15— Br. 4. 



