SILURID^. THE SORUBIN^. 



359 



original definition of this group by Geoffroy' Saint- Hilaire^ 

 we shall here repeat what has been said on it by Cuvier. 

 He observes : '^ It has the head furnished with a rough 

 flat buckler, broader than in any other Silurus, because 

 the frontals and parietals give out lateral plates, which 

 cover the orbit and the temple : the operculum is still 

 smaller than in the preceding genera (as Doras, Age- 

 niosus, &c.) ; and what distinguishes these from all 

 other fishes, is the peculiarity observed by M. Geoffroyj 

 that, independently of the ordinary branchiae, they have 

 (an) apparatus ramified hke trees, adhering to the 

 superior branch of the third and fourth branchial arch, 

 and which appear to be a sort of supernumerary gills : 

 for the rest, their viscera resemble those of the other 

 Siluri. Their branchial membrane has from eight or 

 nine to thirteen or fourteen rays : their pectoral spine 

 is strong and dentated ; but nothing of this is to be 

 found in the dorsal and anal : their body is naked and 

 elongated, as are also the dorsal and anal fins; there 

 is no spine to the dorsal : the caudal is distinct. Those 

 which are known, have eight barbels : they come from 

 the Nile, from Senegal, and from some rivers of Asia. 

 Some, (forming the genus ?) Macropteromus Lac. 

 (or ?) Clarias Gronov., have but a single dorsal, alto- 

 gether radiated : others have a radiated and an adipose 

 dorsal." The Heterobranchus 5-tentaculatus of Spix 

 {fi9' 94.) appears to belong to a different division of 



the family ; and the annexed cut will show it has a 

 much greater resemblance to the Sorubince than to the 

 SilurincB. In respect to the singular structure of the 



A A 4 



