374 CHAKACINID.I-:. 



dorsal fin. Anterior dorsal rays rather prolonged ; anterior anal rays 

 produced into a lobe, the other rays gradually decreasing in length. 

 GiU-rakers of the outer branchial arch lanceolate. Coloration uniform . 

 Brazil, Guianas. 



a. Fine specimen. Essequibo. From Mr. Ehrhardt's Collection. 

 6. Young. Guiana. Purchased of Mr. Frank. 



4. Myletes parma. 

 D. 23-24. A. 38. V. 7-8. 



The height of the body is three-fourths of the total length (with- 

 out caudal), the length of the head one-fourth. The upper and lower 

 profiles strongly arched, subsemicircular. Snout obtuse, as long as 

 the diameter of the eye, which is one-third of the length of the head, 

 and two-thirds of the width of the interorbital space. Dentition as 

 normally in this genus. The naked space on the cheek is as high as 

 the second infraorbital bone. The abdominal serrature is composed 

 of thirty-six simple spinous plates, the spines being rather prominent. 

 Anterior part of the dorsal fin rather high ; it commences a little 

 nearer to the extremity of the snout than to the end of the lateral 

 line, and the length of its base is exactly one-third of the total (with- 

 out caudal). Adipose fin well developed, its length being more than 

 one-half of its distance from the dorsal fin. Anal fin -with the third 

 ray strong, cartilaginous, not quite as long as the head ; the middle 

 and the hinder portion of this fin are rather low, the margin being 

 nearly straight. Caudal fin emarginate, with the lobes pointed. 

 GiU-rakers of the outer branchial arch lanceolate, of moderate length. 

 Coloration imiform ; vertical fins with a broad blackish margin. 



Para. 

 a-b. Eight inches long. Eiver Capin. Purchased of Mr. Stevens. 



5. Myletes macropomus. 



Cuv. Mem. Mus. iv. p. 453. pi. 21. tig. 3 : Cuv. ^ Val. xxii. p. 195 ; 

 Kner, Denkschr. Acad. JV^iss. Wien, 1860, xviii. p. 20. 



B. 5. D. 16. A. 25. V. 8. L. lat. 80. 



The height of the body is one-third of the total length (with the 

 caudal), the length of the head one- fourth. None of the fin-ra3's 

 prolonged ; adipose fin small, rayed. Operculum large, its width 

 being contained only once and two-thirds in its depth. The infra- 

 orbital ring covers the cheek entirely. Coloration uniform. 



Brazil. 



6. Myletes brachypomus. 



Myletes brachypomus, Ckv. Mem. Mus. iv. p. 452. pi. 22. fig. 1 ; Cuv. 



^ Val. xxii. p. 199 ; Kner, Denkschr. Acad. Wiss. Wien, 1860, xviii. 



p. 21. 

 ? Myletes pacu, Humb. Observ. Zool. ii. p. 175. pi. 47. fig. 2 (very bad). 



B. 5. D. 16. A. 26. V. 8. L. lat. 105. 



The height of the body is one-third of the total length (the caudal 



1 



