122 VERTEBRATES: FISHES. 



STURGEONS. 



Sturgeons are fishes whose skeleton is a sort of carti- 

 lage, instead of being bony, as in those already described. 

 They are also covered with bony plates placed in rows 

 along the whole length of the body, and the mouth is 

 under the snout, and can be much protruded. They 

 inhabit lakes and the ocean, and ascend rivers. They 

 are from three to ten feet long. See Figure 234. 



SHARKS, OR SELACHIANS. 



These are marine fishes which have the skeleton 

 cartilaginous, and which, in many cases, are very large, 

 and in most cases very ferocious. The different kinds 

 vary from four to thirty feet in length, and their teeth 

 are very numerous, sharp as lancets, and inflict the 

 severest wounds. The smaller marine animals and 

 even men fall a prey to them. 



The Rays, or Skates, have the body broad and flat, 

 and are from two to six feet or more in length, and as 

 wide or wider than the length. Those called Vampires 

 are sometimes sixteen feet wide, and weigh several tons! 

 One kind of Ray, called Torpedo, gives violent electrical 

 shocks when touched. See Figures 242 and 243. 



SUCKERS, OH CYCLOSTOMES. 

 The true Suckers are the least perfect or lowest of all 

 the fishes, and their tongue moves forwards and back- 

 wards like the piston in a pump, enabling them to pro- 

 duce a vacuum, and thus to fix themselves to other 

 fishes. The Sea Lamprey, two or three feet long, the 

 Hag or Myxine, six or eight inches long, and the Am- 

 phioxus, or Lancelot, are of this kind. The last two 

 also live in the sea, and are seldom seen. The Lam- 

 prey ascends rivers, and piles up heaps of stones, among 

 which it lays its eggs. See Figures 244-246, 



