.68 SILURIBiE. 



length (without caudal) . Barbels thin, those of the maxillae scarcely 

 longer than the head. (Agass.) 

 Northern Brazil. 



2. Hypophthalmus longifilis. 



Cui: cy Val. XT. p. 230. 



B. 14. D. 1/6. A. 64-68. P. 1/15. V. 6. 



The length of the head is one-fourth of the total length (without 

 caudal). Maxillary barbels longer than the head, extending beyond 

 the dorsal in the young ; mandibulary barbels with a narrow fringe 

 along their inner margin. Dorsal spine much more feeble and shorter 

 than the slender pectoral spine, the length of which is one-half of 

 that of the head. 



Guiana. 

 a. Adult. Demerara. Purchased of Mr. Scrivener. 

 h-c. Adult and half-grown : stuffed. Demerara. Purchased of Mr. 



Scrivener, 

 d. Half-grown. Surinam. Purchased of Mr. Fyank. 



3. Hypophthalmus marginatus. 



Hypophthalmus marginatus, Cuv. ^- Val. xv. p. 22.5. pi. 439. 

 Notophthalmus marginatus, HyHl, Denkschr. Akad. Wiss. Wien, xvi. 

 1859, p. 17. 



B. 14. D. 1/6. A. 63-68. P. 1/14. V. 6. 



The length of the head is two -sevenths of the total (without 

 caudal). MaxiUary barbels longer than the head, not extending on 

 to the end of the pectoral ; mandibulary barbels compressed, but 

 not fringed. Dorsal spine feeble, half as high as the body ; pectoral 

 spine slender. Top of the dorsal and hinder margin of the caudal 

 black. {Vol.) 



Cayenne and Surinam. 



4. Hypophthalmus flmbriatus. 



K)ier, Sitzgsher. Wien. Acad. 1858, xxvi. p. 444. fig. .30. 

 B. 13-14. D. 1/6. A. 67-68. P. 17. V. 6. 



The length of the head is one-fourth of the total (without caudal). 

 The maxillary barbels have a narrow fringe, and extend on to the 

 end of the pectoral ; mandibulary barbels broadly fiinged, the an- 

 terior being nearly half as long as the entire fish. Dorsal fin low, 

 the length of its feeble spine being two-fifths of the height of the 

 body. Pectoral spine flexible. (Kner.) 



Rio Negro. 



