RAYS — LAMPREYS AND HAG-FISHES 



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invertebrates or fishes. It is much hunted for the sake of its oil, of which a 

 specimen 314 feet in length yielded no less than 198 gallons. A commoner species, 

 the rough hound (Scy Ilium canicula), which sometimes reaches just over 

 40 inches in length, but is generally smaller, preys upon small fishes and marine 

 worms, digging for the latter in the sand. Its range extends from the Mediterranean 

 all round the coasts of Europe. In colour this shark is reddish blotched with brown. 

 Its relative the nurse-hound (»S'. catidus) does not range so far north, but attains 

 larger dimensions, being known to reach a length of 4 feet. It may be distinguished 

 by the circumstance that the oval fin terminates below the second dorsal instead 

 of between the two dorsals. 



The electric rays are so called on account of the presence of an 

 electric organ between the head and the pectoral fin. Of the half- 

 dozen members of the group (all of which can give a powerful shock) the common 

 torpedo {Torpedo nobiliana) reaches about 4 feet in length, and inhabits the 

 Mediterranean and the Atlantic as far south as Madeira. More familiarly known 



Rays. 



HAG-FISH 



are the true rays, or skates, among which the common skate (Raia bat is) is largely 

 used as a food-fish on the European coast of the Atlantic. This species also ranges 

 into the Mediterranean, the North Sea, and the Baltic. 



Another well-known representative of the group is the thornback skate 

 (R. clavata), the skin of which is protected by spines and tubercles, irregularly 

 dotted all over the back. Even more formidable is the sting-ray (Trygon pastinaca), 

 whose body is pear-shaped, while the long tail, in lieu of fins, is armed with a 

 serrated spine capable of inflicting a dangerous wound. This species is found in 

 both the North Atlantic and North Pacific, where it is most abundant in the 

 warmer zones. Of the whip-rays, so called from their whip-like tails, the most 

 notable are the ox-ray (Dicerobatis giorncv) of the Mediterranean, and the devil- 

 fish (D. diabolus) of the West Indies, the latter attaining a length of 10 feet, 

 with a diameter of 18 feet. 

 Lampreys and Following after the true fishes come the lampreys and hag-fishes, 



Hag-Fishes, which are included by naturalists in a class by themselves. Both 

 prey on fishes, but whereas lampreys attach themselves to the outside, hag-fishes 



