THE SHARKS AND RAYS. 427 



Irish coasts. It grows, according to Day, to a length of 4 

 feet, and is easily recognised by the sharp spine before 

 Spur-dog or eacn dorsal fin. The teeth of this dog-fish are 

 Picked Dog. somewhat peculiar, being small and having 

 the inner edge the sharpest. The eyes are large, as also 

 are the spiracles behind them ; and there is no nictitating 



membrane. In colouring this fish is grey above, white on 

 the belly, occasionally dashed with faint yellow, and in 

 young examples having some white spots. In certain 

 internal characters, this and the following sharks agree 

 somewhat closely with the rays. This fish is viviparous, 

 and seems to breed at various seasons. 



A large allied species, growing to a length of 15 feet at 

 least, the Greenland Shark is another of the whale's most 

 Greenland formidable enemies. As its name implies, it 

 Shark. i s an inhabitant of the colder northern seas, 



only visiting the Scottish, and still more rarely the Eng- 

 lish, coast at irregular intervals. The colour of this fish is 

 grey, lighter beneath ; and its chief peculiarities are that 

 the body is covered with small tubercles, and the fins are 

 very small, the dorsal fins having no spines. The teeth in 

 the lower jaw show the peculiarity noticed in those of the 

 last, and they lie in six rows. This shark is viviparous, 

 and is said to produce three or four young only at a birth. 



The entire body of the large Spinous Shark, which 

 grows to a length of over 8 feet, is covered with round 

 tubercles. Like the last, it has all the fins of small size, 



