the intervention of the fh-m but impartial justice of the Romans. These mormyrids, which 

 are entirely African fishes, are strange creatures with a proboscis-like snout ending in a tiny 

 mouth ; with this they root in the mud and crannies to suck in small prey. They spawn among 

 the vegetation along the river banks. One of them (I lele.ro pisns bebe) lays bare the roots of 

 reeds as a place for its eggs. After four days' incubation the larvae that hatch attach them- 

 selves to the roots by means of mucous threads secreted by special glands on the head. At 

 the end of five or six days, having digested the yolk sac, they leave their supports and begin 

 to swim in the muddy waters. Gymnarelnis nilolicns is a small eel-like mormyrid without 

 pelvic fins ; it builds a four-cornered nest among the reeds. Three sides of the nest float at the 

 surface while the fourth is immersed to a depth of 4 to 8 inches. The larvae, which have large 

 yolk sacs and external gills, develop within this shelter and only leave it when these temporary 

 organs have disappeared. 



The special posture of a cat-fish (Synodonlis batensodaj was not unnoticed by the Egyptian 

 painters of the Pharaonic periods : this cat-fish has the habit of swimming belly-upwards at the 

 surface and this unusual position has led to changes in its colour pattern. The underparts 

 are brown or black, while the back, which is always shaded, is whitish. The electric cat-fish 

 (Malapleriirus eleclriciis), the raad or thunder- fish, lives in African rivers. Moving very slowly 

 and living in partly obscure conditions, it waits for some prey to pass within reach and strikes 

 it down with an electric discharge. The electric organs are formed of transversely directed 

 plates set in a layer of gelatinous tissue between the skin and muscles of the trunk. When its 

 victims are paralysed and dead, the electric cat-fish leaves them to decay a little before eating 

 them. 



In the Nile a serranid fish, Lales nilolicns takes the place of our European perch. It is a 

 voracious animal and a fierce enemy of any of the small fishes belonging to the Cichlidae, a 

 family studied by the French scientist Pellegrin. In the main, these fishes look like wrasses 

 or perches and they are able to live in fresh or brackish water and even to cross an arm of the 

 sea. In the past they came from America and followed the shore-lines of the vanished conti- 

 nent of Archihelenis joining Brazil to Senegal. Then they swarmed in the rivers and lakes of 

 Africa and even reached the Near East for they abound in Lake Tiberias. The legend of the 

 miraculous draught of fishes has been attributed to a massing together of the fishes in this 

 lake. The cichlids are able to tolerate temperature changes as well as those of salinity. The 

 Tilapia of Lake Magadi in Kenya live in waters with a temperature from 40° to 45oG. More 

 characteristic eurythermal and euryhaline types of fishes could hardly be found. They are 

 very voracious and this increases their great vitality. The males are distinguished by humps 

 of fat placed on the back, these being found in both young and very old animals. Some species 

 build nests; others take the fertilised eggs into the mouth, between the gill filaments or in a 

 pocket formed by bones at the back of the throat. The larvae develop in this secure shelter 

 until they are able to look after themselves. Even when they have emerged, the male and 

 female watch carefully over them. 



In the Nile there is a pufTer-fish (Telraodon faliaka) which is related to those that swim 

 among the corals. Its small spines bristle when it takes in air and blows out its abdomen. 

 The ancient Egyptians who called it " chept ", thought this was a form of dissatisfaction. 

 The Arabs thought its round and startled-looking eyes showed terror, and called it fahaka, 

 which name has been adopted in Britain. 



The waters of the cone-shaped Nile delta leading to the sea are full of fishes. Grey mullets, 

 which enter arms of the Nile and the lagoons, are abundant in the brackish waters. 



Most of the Egyptian fish species are met with again in Lake Chad. In the Congo basin, 

 the fauna of which has been described by the ichthyologist Boulenger, characin fishes abound. 

 They are fairly near relatives of the cyprinids, but like the salmonids have a small adipose fin 

 in front of the tail. The many species have very different habits. Some are harmless herbi- 

 vores, while others are fierce predators. Among these latter are the tiger-fishes (Hydrocyon 

 yoliaih), the kelb-el-bahr of the Arabs (and of our terminology), which may reach a length of 

 more than 6 feet. It does not even fear the crocodiles. With its strong teeth it is able to cut 

 through the copper traces of the hooks of fishing-lines. It can only be killed by spear thrusts, 



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