218 PISCES. 



is rough and continues to the dorsal as in Synodontis, and their 

 shoulder bone forms a point behind. 



Some of them merely have the band of small and crowded teeth 

 in the upper jaw.(l) 



In others, the snout is pointed and the teeth are either wanting 

 or are hardly visible; the maxillary cirri are sometimes furnished 

 with lateral set3e.(2) 



Heterobranchus, Geoff, 



The head provided with a helmet that is rough, flat, and broader 

 than that of any other Silurus, a circumstance occasioned by two 

 lateral pieces furnished by the frontals and parietals which cover 

 the orbits and temples. The operculum is still smaller in propor- 

 tion than in the preceding fishes, and what chiefly distinguishes 

 them from all others is the peculiarity observed by M. Geoffroi, 

 that besides the ordinary branchise, they have an apparatus ramify- 

 ing like a tree, adhering to the superior branch of the third and 

 fourth branchial arch, and which appears to constitute a sort of su- 

 pernumerary gills. Their viscera resemble those of other Siluri, 

 and their branchial membrane has from eight or nine to thirteen or 

 fourteen rays. The spine of their pectoral is strong and dentated, 

 but there is none such in the dorsal; their body is naked and elon- 

 gated, as well as their dorsal and anal. There is no spine in the 

 dorsal. The caudal is distinct. All the species known have eight 

 cirri and inhabit the Nile, the Senegal, and some rivers in Asia. 

 Their flesh is indifferent or bad. 



Some of them, the Macropteronotes, Lacep., or the Clarias, 

 Gronov., have but a single radiated dorsal. 



One of these, the Sharmuth, or Black-Fish, Silurus anguilla- 

 ris, Hasselq. and L., is common in Egypt and in Syria, consti- 

 tuting in the latter a considerable article of food.(3) 



(1) Silurus costaius, L., Bl., 576, and Gronov., V, 1, 2, which is also the Cata- 

 phradus americanus, Catesb., Suppl., IX, usually quoted as Sil. cataphr actus; 

 Sil carinatus, Lacep., which appears to ine the same as Gronov., Ill, 4 and 5, gen- 

 erally cited also as the S. caiaphr actus, and as the Kliji-hagre, Marcgr., 174, thus 

 reducing the *S'. cato^Aradwfi to nothing. i^oras gmnu/ow, Valenc, App. Humb 

 Zool., Obs., II, 133. ' 



(2) Doras niger, Valenc, loc. cit., or Corydoras edentulus, Splx, V;I)or. ox- 

 yrhynchus, Val., lb. 



(3) Add Macropt. magur, Buchan. XXVI, the same as the Silurus called anguil- 

 laris by ratr. Russel, 168; -SiY. hatrachus, BL, 370, 1, which may be the same as 

 the Macropt^ronote hrun, Lac, V, ii, 2j the hexacircinc has only six cirri, but it 

 rests merely on Chinese drawings. 



