GENERA AND SPECIES. 



female having 2 dark blotches at the base of the dorsal rays, and a 

 third one at the root of the tail. This species is 13 inches long, and 

 is found not in sandy bays, but on rocky coasts, where the molluscs 

 and crustaceans that form its food are abundant. It is frequently 

 caught in crab-pots, which it enters to feed on the bait. 



Lsemargus. Plate xxx. SPINACIDJE. 



234. borealis, GREENLAND SHARK. Body stout ; dorsals without 

 spines ; anal fin absent. 



In the Greenland Shark the fins are all small in proportion 

 to the girth of the body. The first dorsal is in the middle of the 

 back, and also half-way between the pectorals and ventrals. The 

 second dorsal begins above the hinder edge of the ventrals. The 

 lower lobe of the caudal fin is much larger than the upper. 

 The snout is prolonged, and the curve from its tip to the mouth is 

 that of a clipper bow. The mouth extends to the eye, which is 

 small and without a lid. The gill-slits are small. This is an Arctic 

 species, known only as a straggler in British waters. It reaches 25 

 feet in length, and is grey above, lighter below. 



Lamna. Plate xxviii. LAMNID&. 



226. cornubica, PORBEAGLE. Body stout; side of tail keeled; anal 

 fin present. 



This is the second of the three stout-bodied sharks in our list, 

 the third being the Basking Shark. It is distinguishable by the 

 large size of its first dorsal, caudal, and pectoral fins. The second 

 dorsal and anal are small and opposite. The first dorsal is half- 

 way between the snout and the second dorsal, and the ventrals are 

 halfway between the two dorsals. The upper lobe of the caudal is 

 large, and notched near the tip. Along the side of the tail there is 

 a conspicuous keel. It is fairly common, and attains a length of 9 

 feet, the colour being greyish above and whitish below. 



Lampris. Plate v. CORYPHSENID&. 



33. luna, OPAH. Iridescent, with oval silver spots ; fins pointed. 



This is the moat brilliantly coloured of British fishes. There are 

 from 53 to 55 rays in the dorsal fin ; 38 to 41 in the anal ; 22 in the 

 caudal ; 24 in the pectorals, and from 14 to 16 in the ventrals. The 

 dorsal is very long in front, and in about a quarter of its length 

 suddenly shortens and becomes very low and level with the back 

 until near the end. The anal is low and straight ; the caudal is 

 deeply forked ; the pectorals are pointed, and extend beyond the 

 middle of the dorsal. The lateral line is a semicircle for half its 

 length, and then becomes perfectly straight. The shape is a deep 

 oval, the body being flat. In colour it is best described as iridescent, 

 the reds, greens, blues, and purples mingling and changing according 

 to the point of view, the conspicuous feature being a number of 

 large, well-defined oval spots of silver. The fins are mainly red. 

 In size the Opah attains 6 feet. Notwithstanding its bright colours 

 it seems to be a northerly fish, and is only found in deep waters. 

 Though not common, it has been frequently taken in the North Sea. 



