304 COMPARATIVE ZOOLOGY. 
Fie. 281.—Shark (Carcharias vulgaris). Atlantic. 
marine. The largest Shark found, and therefore the 
largest Fish, measured thirty-five feet. 
6. Dipnoi, or Mud-tishes (Lepidosiren), of tropical 
rivers. They form a link between the typical Fishes and 
Fic. 282.—Thornback (Raia clavata). European seas. 
