LECTURE VIII. 73 



its general habits. It sorhetirnes is seen to swim 

 with a considerable degree of swiftness^ but is 

 more commonly found adhering by the mouth to 

 some large stone or other substance, to which it 

 clings so powerfully as to require a great degree 

 of force to separate it. As an article of food the 

 Lamprey has long been celebrated. Its usual 

 colour is a dull yellowish-white, clouded with 

 brown or olive-coloured variegations. All the 

 rest of the genus are of much smaller size, but in 

 shape and way of living resemble the great Lam- 

 prey, except that they are confined to rivers. 



The next genus of the Cartilaginous Fishes 

 consists of the Ray or Skate tribe, and is charac- 

 terized by a flattish body, in some of a lozenge- 

 shape, in others rounded, and in all furnished with 

 a lengthened tail : the mouth is placed beneath 

 the head, and is furnished with very numerous 

 small teeth generally covering the lips or edges of 

 the mouth ; and on each side the neck beneath* 

 are placed five large transverse slits or openings 

 leading to the gills. The common Skate furnishes 

 a good example of this genus, and is the Raja 

 Balis of Linnasus. It often grows to a vast size, 



