122 silurid^:. 



13. Fimelodus guatemalensis. 

 D. 1/6. A. 13. P. 1/9. 



Head covered with thin skin above. The adipose tin is long, two- 

 fifths of the total length (without caudal) ; it is separated from the 

 dorsal and caudal by a short interspace. The maxillary barbels ex- 

 tend to beyond the origin, or to the middle, of the adipose fin ; the 

 outer ones of the mandible to, or nearly to, the extremity of the 

 pectoral. 



The height of the body is one-sixth of the total length (without 

 caudal), the length of the head one-fourth; the head is depressed, 

 its greatest width being three-fourths of its length ; the diameter of 

 the eye is one-third of the extent of the snout, and two-fifths of the 

 width of the interorbital space. The least depth of the tail is two- 

 fifths of the length of the head. The lower jaw is a little shorter 

 than the upper ; the band of intermaxillary teeth six times as broad 

 as long. Dorsal fin with the spine very feeble, scarcely higher than 

 long. Pectoral fin short, half as long as the head ; its spine is a 

 little longer than that of the dorsal fin. No porus mucosus in the 

 axil. Ventral fin a little shorter than the pectoral. The length of 

 the anal equals that of the dorsal ; its posterior rays extend to the 

 end of the adipose fin if laid backwards. The lower caudal lobe is 

 the longer, its length being rather more than one-sixth of the total. 

 Brownish black, the lower parts whitish ; dorsal fin with a very in- 

 distinct lighter longitudinal band. 



Guatemala. 

 a-b. Twelve inches long. Huamuchal. Lakes with brackish water. 

 From the Collectior of Messrs. Godman and Salvin. 



14. Pimelodus breviceps. 



Pimelodus breviceps, Kner, Sitzgsber. Wien. Acad. xxvi. p. 41$. 



D. 1/6. A. 12. P. 1/8. 



Head covered with thick skin. Adipose fin very long, commencing 



and terminating at a short distance from the dorsal and- caudal. The 



maxillary barbels extend to the anal, the outer ones of the mandible 



to the posterior third of the pectoral. 



Snout narrow, somewhat pointed ; the length of the head is con- 

 tained six times and a half in the total (with the caudal) ; the eyes 

 are situated nearly in the middle of the head, their diameter being 

 one-half of the width of the interorbital space. Dorsal fin more 

 than twice as high as long. Porus axillaris small. Caudal fin deeply 

 forked, with the upper lobe longest, its length being more than one- 

 fifth of the total. (Kner.) 

 Marabitanos. 



15. Pimelodus wilsoni. 



Pimelenotus vilsoni, Gill, in Ann. Lye. Nat. Hist. Netv York, 1858, 

 p. 391. 



D. 1/6. A. 10. P. 1/8. 



Head covered witn thin skin above , the occipital process does not 



