2. HETEROBEANCHXJS. 21 



of the intermaxillary. Head very finely granular above, its length 

 being one-sixth, or somewhat less than one-sixth, of the total (with 

 the caudal). Barbels long ; the nasal extending to the end of the 

 head, and that of the maxillary to, or beyond, the extremity of the 

 pectoral. Pectoral fin short, not reaching the vertical from the origin 

 of the dorsal. 



East Indian Archipelago. 



a. Fifteen inches long. Purchased of Mr. Frank. 



b. Half-grown. Philippine Islands. From Mr. Cuming's Collection. 



According to Bleeker the number of the dorsal rays would vary 

 between 87 and 106, and that of the anal rays between 69 and 95. 



19. Clariasjag^r. 



Macropteronotus jag-xu', Ham. Bitch. Fish. Gamj. p. 145. 

 Clarias jagur, Cm\ ^- Vol. xv. p. 388. 



Cossyphus (Phagoriis) ater, M'Clell. Calc. Juiirn. iv. p. 403. pi. 22. 

 fig. 3 (mutilated), and v. p. 225 (EiTata). 



D. 53. A. 50. 



Caudal fin imited with dorsal and anal. 

 Ganges. 



2. HETEEOBRANCHUS*. 



Ileterobranchus, Geoffr. St.-IIU. 



The back is occupied by a long dorsal fin divided into two portions, 

 an anterior which is rayed, and a posterior which is adipose ; anal 

 long. A band of viRiform teeth across the vomer ; cleft of the mouth, 

 the eight barbels, the armature of the head, the gill-apparatus with 

 the accessory organs, the ventral and pectoral fins, as in CJanas. 



Africa and East Indies. 



The structure of the dorsal fin is almost the only point of import- 

 ance in which the genus Ileterobranchus difters from Clarias ; how- 

 ever, we must remark, that in well-fed specimens of the latter genus 

 the whole fin assumes an adipose appearance, in consequence of a 

 thick layer of fat deposited along the base ; and that, on the other 

 hand, very distinct traces of rays may be seen in the adipose fin of 

 Heterobranchns. 



The skeleton docs not differ from that of Clarias, except that the 

 neural spines of that portion of the caudal vertebral column which 

 corresponds to the adipose fin are much longer, the interueural spines, 

 of course, being absent. 



1. Heterobranchus bidorsalis. 



Heterobranchus bidorsalis, Geoffr. Dcscr. Ey. Atl. Poiss. pi. 10. fig. 2. 

 geoffrovi, Cuv. l^- J'af. xv. p. 392. 



B. 12-13. D. 44. A. 52. P. 1/10. Yert. 21/42. 

 The length of the adipose fin is rather less than two-thirds of the 

 rayed dorsal ; pectoral spine slightly serrated. The na.sal barbels 



* 1. Heterobranchus senegalensis, Cuv. ij" Va(. xv. p. 397. —Senegal. 



