n CHARACTERISTICS OF VALUABLE MARINE FISHES 43 



the same thing is done to the plaice or turbot the one half will 

 be the back of the fish and contain the brain, the other will be 

 the belly half and contain the gills and intestines. The great 

 breadth of the skates and rays is due to the enormous size of the 

 breast fins, which extend from the hinder fins nearly to the tip 

 of the snout, passing above the gill-openings, and it is from this 

 cause that the gill-openings arc on the lower surface of the fish. 

 The tail is correspondingly reduced, forming a whip-like ap- 

 pendage on which the two small dorsal fins are placed. 



Skates and rays are coast fishes, not occurring at depths 

 beyond 500 fathoms, and they occur in greater or less abundance 

 in all parts of the world : in the large rivers of tropical regions 

 many kinds live entirely in fresh water. 



The monk-fish or angel-fish, which is not uncommon in the 

 English Channel and North Sea, although usually classed in the 

 dog-fish division, shows us as it were the skate in process of 

 manufacture. The body is flat, the breast fins large, and the 

 fish rests on the ground, but the breast fins do not extend forwards 

 to the head and do not entirely cover the gill-slits above ; the 

 hinder fins are not very much smaller than the breast fins, and 

 there is no sudden decrease of size between the body and tail. 

 Of skates and rays there are several families, the principal 

 being the electric rays, the common skates and rays, and two 

 families of sting-rays. All these are represented in British 

 waters. One kind of electric ray or torpedo reaching four feet 

 in length is often taken in trawls on the south coast and in 

 the North Sea. In the electric rays the front edge of the body 

 is quite straight. In the sting-rays, commoner off the south 

 coast than elsewhere, there are no fins on the tail, which is long 

 and cord-like, but a strong spine with toothed edges projects 

 from its dorsal side not far from the base. 



The commoner rays, which are largely used as food, consist 

 of several kinds in two groups, the long-snouted kinds and the 

 short-snouted. The former are always distinguished as skates 

 by fishermen, the latter as rays or roker. The common 

 skate (Fig. 5) is distinguished by having a smooth skin and 

 having the lower surface coloured a bluish-grey nearly all 

 over. The flapper skate is rough on the back, and white 

 beneath; the white skate and the long-nosed skate are two 

 other large and common species. Of the rays the commonest 



