278 



SILTJE1DJE. 



CLARIAS. 



Gronovius, Zoophyl. p. 100 (1781) ; Giinther, Cat. Fish. v. p. 248 (1864) ; Boulenger, Poiss. Bass. 



Congo, p. 248 (1901). 

 Macropteronotus, part., Lacepede, Hist. Poiss. v. p. 84 (1803). 



Body elongate, with long dorsal and anal fins composed entirely of soft rays, 

 extending to or nearly to the caudal fin. Pectoral fin with the outer ray spinous; 

 ventral fin with 6 rays. Head much depressed, the upper and lateral parts osseous, 

 forming a casque ; four pairs of barbels— one nasal, one maxillary, two mandibulars. 

 Eye small 5 with free orbital margin. Jaws with a band of villiform teeth ; a band of 

 villiforra or granular teeth on the vomer. Gill-membranes free from the isthmus, 

 deeply notched in the middle. A dendritic, accessory branchial organ attached to the 

 second and fourth branchial arches and received in a cavity behind the gill-cavity 

 proper. Air-bladder small, bilobed, disposed transversely and partially enclosed in a 

 bony sheath formed by the transverse processes of the fourth and fifth vertebrae. 



The vertebrae number 60 to 78 (65 to 67 in C. anguillaris and C. lazera, 60 in 

 C. carsonii). Nine branchiostegal rays. Males with a long, conical, anal papilla. 



The highly vascular arborescent structures which surmount the gills (see 

 PL XLIX. fig. c) enable these fishes to breathe atmospheric air. The Clarias are 

 regular amphibious animals which can spend the dry season in burrows in dried-up 

 marshes, which they leave at night in quest of food *, consisting of both animal and 

 vegetable matter. 



The genus Clarias is represented in South-eastern Asia, Syria, and Africa. The 

 number of African species amounts to thirty-two. Their distinction is beset with oreat 

 difficulties, and most of my predecessors have attached too much importance to the 

 comparative length of the barbels in defining species. How variable these appendages 

 may be is shown by the description of Clarias lazera, and especially by the table of 

 measurements which accompanies it. As a rule, the barbels are proportionally longer 

 in the young, in which the spine of the pectoral fin is also shorter. 



Heckel f has referred to " Clarias hasselquistii " a figure in the great fishing-scene 

 painted in the tomb near the Pyramids of Giza $. Characteristic representations of 

 C. anguillaris or lazera are those in tomb 15 of the Pyramids of Sapara§, and in the 

 tomb of Ti, at Sakkara, as I see from an unpublished photograph kindly shown me by 



* Of Vaillant, Bull. Mus. Paris, 1895, p. 271. 

 t Eussegger's Eeise Egypt, iii. p. 316. 

 X Of. Lepsius, Denkmaeler, Abth. ii. pi. ix. 

 § Of. Lepsius, op. cit. pi. xlvi. 



