174 FROGS, TOADS AND SOME FRESH-WATER FISH. 



the rivers of Chihli and southward, but I have not come across it in the 

 west. The same species occurs in Northern Asia and Europe, and is 

 very common in Great Britain. 



Another little fresh water fish is the stickleback (Gastrosteus 

 sinensis) recorded b.y David. I have never seen a specimen, but it is 

 said to inhabit the waters of Chihli. Sticklebacks are noted for build- 

 ing nests, in which to lay their eggs, guarding the latter against all 

 invaders with a spirit and reckless daring one would hardly expect in 

 so low a form of life. They make splendid additions to the aquarium, 

 being probably more interesting, because having more character 

 and more remarkable habits, than any other fish. The males are fierce 

 fighters and ardent wooers. They tease, it would almost seem for the 

 mere fun of the thing, the other inmates of the aquarium. In the mat- 

 ing, season the males, at least in the common three spined species of 

 British streams, are brightly coloured with crimson and blue. 



The serpent-head (Ophioccphalus argus) is a peculiar fish that 

 occurs in great numbers in all the waters of Chihli. It derives its name 

 from the marked resemblance of its head to that of a snake. This is 

 very long in shape, with the eyes set well forward. The markings also 

 add to the illusion. The body is long, with a fin extending along the 

 whole length of the back, and another along the ventral surface, from 

 behind the belly, which is well forward. The tail is rounded. The 

 whole of the body is marked with bars and blotches of a dark olive-grey 

 colour upon a lighter ground. The fins and tail are spotted. This fish 

 can withstand periods of drought, when it burrows into the mud and 

 apparently becomes torpid. It is also common in the Manchurian 

 rivers, though it may be looked upon more as a swamp than a river 

 fish. The flesh is coarse. The Chinese name is Hei-yu (Black fish). 



Related to the serpent-head is the beautiful little paradise-fish 

 (Poly acanthus opercularis), which is supposed to be a cultivated variety 

 of some hitherto undiscovered wild species. In South-east China 

 several species inhabit the rivers. The domestic species is of a golden 

 colour barred with red. It has greatly elongated dorsal and anal fins 

 and tail. It is very easy to keep, and breeds freely. 



The wels (Silurus assotis) belonging to the catfish tribe is very 

 common in the muddy waters of the North China rivers. It might 

 well be called the mud-fish, were it, not that the name is already used to 

 designate certain lung-fishes of South Africa and South America. The 

 wels has a long, somewhat eel-like body, a large head with an enormous 

 mouth. The latter has several pairs of long filamentous appendages 



