CHELONIAN KEPTILES. 401 



The Leather-backed Turtle (Sphargis) (Fig. 333 , instead of 

 horny plates, is covered with a leathery skin, marked by several 

 ridges running lengthways down the baclv. These animals are 

 amongst the bulkiest of the race, and have been known to measure 

 nine or ten feet. Tliey have a remarkable cry, and when caught in 

 the net utter a loud roaring sound, whence they derive their name 

 Sphargis, from the Greek {acpapayiCo}, spharaglzo), which means to 

 move with a noise. 



In tlie great rivers and lakes of both hemispheres 

 there are some laro-e and ferocious creatures, known 



as — 



The Soft Tortoises (Trionyx). These have no horny shell, but 

 are covered by a soft skin, occupying the centre of the back, and sur- 

 rounded by a broad margin of firmer texture (Fig. 334). Their feet 

 are webbed, but three toes of each are furnished with powerful claws, 

 whence their name Trionyx (three-clawed). The beak is horny, and 



Fig. 334.— soft tortoise 



partly concealed by fleshy lips, and their muzzle is extended into a 

 short proboscis. These animals are eminently carnivorous, and 

 piusue fishes and young crocodiles, which they catch in the water. 

 Notwithstanding tlie natm-e of their food, their flesh is esteemed for 

 the table, and hence they are caught with a hook and line. In seiz- 

 ing their food or defending themselves, they dart out their long neck 

 with the sudden rapidity of an arrow. The grasp of their powerful 

 and trenchant beak is sharp and deadly, nor is it relaxed until the 

 part seized is cut out. Indeed, such is their boldness and ferocity, 

 that they are dreaded- even by those who fish for them. 



The Marsh Tortoises {Emys) form a very numerous family, 

 including seventy-four out of the one hundred and twenty species 

 known to belong to the order. More than half of them are Ameri- 

 can. They resemble the common Land Tortoises in their general 

 appearance, but are flatter, and their toes are connected by a web. 

 They inhabit fresh waters, in wliich they swim with facility, and are 

 often found in stagnant poncls and morasses. They feed on small 

 aquatic animals. Many species are esteemed for the excellence of 

 their flesh. The common European Terrapin (Terrapeiie Europma) 



