454 TUBE-BLADDERED GROUP. 



many of which contain a multitude of species. In this work only a very few 



of the genera can be even mentioned, some of those selected including the largest 



members of the family. 



Clarias anguillaris is a well-known representative of the first 



subfamily, in which the long dorsal and anal fins extend nearly 



throughout the length of the trunk, It belongs to a minor group confined to 



Africa and the Oriental region, and characterised by the dorsal fin being either 



composed of weak rays throughout its length, or with its hinder portion modified 



into a fatty fin. 



The wels (Silurus qlanis), shown in the larger figure of the 

 Wels . . . 



illustration on p. 436, is the typical representative of the second 



subfamily, in which the rayed dorsal fin is but little developed, and if present at 

 all occupies only the hinder region of the trunk ; the fatty portion being small or 

 wanting. The anal fin is not much shorter than the caudal region of the backbone,, 

 and the pelvic fins are behind or below the dorsal. In the wels and its congeners the 

 short dorsal has no pungent spine ; the fatty fin is wanting ; there are two upper and 

 two or four lower barbels ; the head and body are naked ; and the tail-fin is rounded. 

 The wels itself, which is confined to the European rivers eastwards of the Rhine, 

 has six barbels, of which the upper pair are considerably longer than the head, and 

 commonly attains a length of from 6 to 9 feet, although it occasionally grows to 

 1-3 feet. In colour the head, back, and edges of the fins are bluish black, the sides 

 greenish black spotted with olive-green, and the uncler-parts reddish or yellowish 

 white with blackish marblings. Frequenting rivers and lakes with muddy 

 bottoms, the wels feed on fishes, frogs, and crustaceans, but it will also seize and 

 pull down ducks, geese, or other birds swimming on the surface. The spawning- 

 time is in the middle of summer, when these fish resort to the shallows in order 

 to deposit their eggs on the stems and leaves of water-plants. 

 Yarreirs Cat- Another gigantic species is Yarrell's cat-fish (Bagarius yarrelli), 



Fish, etc. from the large rivers and estuaries of India and Java, which attains 

 a length of fully 6 feet, and from its huge head and mouth is one of the ugliest 

 fishes in existence. The only member of its genus, it belongs to a subfamily in 

 which the rayed dorsal fin is short, and situated in the hinder part of the body in 

 advance of the pel vies ; and there is always a fatty fin, which may, however, be 

 short : and the anal is shorter than the caudal region of the backbone. When 

 nasal barbels are developed, they belong to the hinder nostrils. In the group of 

 genera to which Yarrell's cat-fish belongs the front and hinder nostrils are placed 

 near together, with a barbel between them ; and in this particular form there are 

 eight barbels, and the upper surface of the head is naked. This gigantic species is 

 of especial interest on account of its fossilised remains occurring in the Pliocene 

 deposits of the Siwalik Hills in North-Eastern India. 



The well-known genus Arias, from all the tropical regions of the world, 

 belongs to another group of the same subfamily, in which the front and hinder 

 nostrils are close together, but have no barbel, although the hinder-pair are provided 

 with a valve. The Tropical American genus Pimelodus is the typical representa- 

 tive of a third group of the same subfamily, in which the two pairs of nostrils are 

 ecpaally devoid of barbels, but are placed at a considerable distance apart. The 



