114 FISH GALLERY. 



custodian. The eggs of Arius are large, of about the size of 

 cherries (1146, Cabinet-case 29). 



Clarias (359) occurs in the muddy and marshy fresh waters of 

 Africa and South Asia, Copidoglanis (361) occurs in Asia and 

 Australia, and Saccobranchus (362) in the rivers of the East 

 Indies. 



Doras (379) is distinguished by a series of bony scutes along 

 the middle of the side. It travels over land in the dry season in 

 search of a pond of greater capacity ; its progress is fairly rapid, 

 and is effected by a springing movement of the tail, the spines of 

 the outspread pectoral fins serving to prevent the body from rolling 

 over sideways. These fishes make nests and both sexes tend the 

 eggs. They occur in those rivers of tropical South America that 

 flow into the Atlantic. 



Schal. Synodontis of the African rivers has a way of floating belly up- 



wards at the surface of the water, a curious habit which is 

 represented in many of the drawings of the ancient Egyptians. 

 One of the commonest species of the Nile is the Schal, Synodontis 

 schal (skeleton, 382), which grows sometimes to two feet in length. 



Electric The Electric Cat-fish, Malopterurus electricus (383, and fig. 56), 

 a fish not uncommon in the fresh waters of tropical Africa, has no 



Fig. 56. — Electric Cat-fish, Malopterurus electricus. 



front dorsal fin ■ it has a large adipose dorsal set far back, and a 

 short-based anal fin. The skin is soft and velvety, without scales 

 or scutes ; the gill-opening is narrow, a mere slit in front of the 

 pectoral fin. There are three pairs of barbels. The eyes are small, 

 and the fish avoids light and is slow in its movements. The electric 

 organ extends over the whole body beneath the skin, but is 

 thickest on the abdomen. It consists of connective tissue com- 

 partments filled with a firm jelly; it is an organ of cutaneous 



