75. AUCHENIPTERUS. 195 



below the pectoral fin ; a groove between the frontals, open in front. 

 Lower jaw scarcely shorter than the upper ; the maxillary barbels 

 extend beyond the gill-opening. The humeral process reaches back- 

 wards to the posterior third of the pectoral spine. Dorsal spine 

 slightly serrated in front, as long as the head. Caudal obliquely 

 truncated. Small light spots along the lateral line. (Kner.) 

 Rio Guapore. 



3. Auchenipterus trachycorystes. 



Cuv. fy Val. xv. p. 215. pi. 437 (from a stuffed example). 

 D. 1/6. A. 20. P. 1/6. V. 9 or 10. 



The bones Of the head and neck finely granulated ; a round groove 

 between the frontals, surrounded by bone. Lower jaw rather longer 

 than the upper ; maxillary barbels not longer than the head. Pec- 

 toral spine very strong, serrated along both edges, one-seventh of the 

 total length, not extending beyond the extremity of the pectoral 

 process ; dorsal spine nearly as long as that of the pectoral, crenu- 

 lated in front. Caudal truncated. ( Val.) 



Brazil. 



4. Auchenipterus ohscurus. 

 D. 1/5. A. 19-2U. P. ±. V. 9. 



The bones of the head and neck are rattier uoarsely granulated ; a 

 email round groove between the frontals, surrounded by bone. Lower 

 jaw rather longer than the upper; the maxillary and the hinder 

 mandibulary barbels extend to, or somewhat beyond, the extremity 

 of the humeral process ; the anterior mandibulary barbels are twice 

 or thrice as long as the eye. The humeral process extends back- 

 wards beyond the middle of the pectoral spine. Dorsal and pectoral 

 spines serrated, the former along its anterior edge, the latter along 

 both edges ; the dorsal spine is considerably shorter than that of the 

 pectoral fin, the latter being as long as the head, and one-fourth of 

 the total length (without caudal). Caudal fin slightly emarginate, 

 the upper lobe being scarcely longer than the lower. Lateral line 

 irregularly undulated. Uniform brownish black. 



Essequibo. 

 a-b. Eight and a half inches long. Purchased of Mr. Ehrhardt, 



5. Auchenipterus longimanus. 

 D. 1/5. A. 22. P. 1/6. V. 10. 

 The bones of the head and neck finely granular ; groove between 

 the frontals open in front. Jaws equal anteriorly ; the maxillary 

 barbels extend to the middle of the humeral process, the anterior 

 chin-barbels shorter than the eye. The humeral process extends 

 backwards beyond the middle of the pectoral spine. Dorsal and 

 pectoral spines serrated along both edges, the former as long as the 

 head, but much shorter than the pectoral spine, which is strongly 



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