THE SHARKS AND EAYS. 425 



as has already been mentioned, five; but in the present 

 comb-toothed species, which has no near ally in our seas, 

 Six-gilled we find the number of gill - openings to be 

 Shark. ${% indeed there are two allied species in the 



Mediterranean with seven. The large and fierce Six-gilled 

 Shark has been taken on our coasts to the length of nearly 

 30 feet. The single dorsal fin, situate far back over the 

 anal, is without spines. The eye is large, and devoid of 

 nictitant membrane. The spiracles are small, and lie low 

 down on the neck. The mouth is without labial fold, and 

 the teeth are not equally developed in either jaw, several 

 series being in use together. In colour this shark is 

 uniform grey. 



In the dog-fishes we have an important group of ground- 

 sharks, mostly of small size, and feeding on crustaceans 

 and carrion. 



One of the most familiar of these, a fish that grows to 

 a length of at least 4 feet, possibly more, is the spotted 

 Nurse, also known as " Bounce " or " Cat-fish." 

 In colour this dog-fish is reddish brown on the 

 back and sides, and covered with large dark spots, lower 

 surface white. The eye is without nictitant membrane ; 

 the spiracles are of moderate size. I have taken this 

 fish of a length of nearly 3 feet on the rod, and have 

 invariably found it show a tendency to wind itself round 

 my arm, by no means a pleasant sensation, as the skin is 

 very rough, so much so that it is an efficient substitute 

 for emery-paper. This is more eaten than most of our 

 sharks and dog-fish. It feeds, chiefly at night, on crus- 

 taceans. It is oviparous, the "purses" being deposited in 

 the autumn. I have observed on the nostrils of this fish 

 folds similar to those alluded to by Mr Dunn in the black- 

 mouthed dog-fish, and denoting in all probability smelling 

 powers of a high order. 



The most remarkable property in the allied How Hound, 



