THE SHARKS AND RAYS 87 



gusted fishermen have been able to disentangle them from 

 their mackerel nets. 



The feature of this shark which must at once strike the 

 observer is its great depth in proportion to length — in fact, its 

 marked departure from the typical symmetry of round fishes, 

 which explains its want of agility in the water. Only its huge 

 relative, the basking shark, is similarly proportioned, and with 

 that species there is little risk of confusion. Apart from this 

 clumsy shape, it must be confessed that the porbeagle is 

 wanting in distinguishing characters. It has no characteristic 

 hue, like that, for instance, of the blue shark, and no spots cw 

 blotches, as are found in the nursehound and rowhound. 

 Most other external features it shares with other sharks. The 

 conspicuous notch In the upper lobe of its tail is equally 

 noticeable in the blue shark, which belongs to a totally 

 different family, and that species also has the curious pores 

 that stud the porbeagle's snout. Its breathing spiracles are 

 generally very minute, but so are those in the tope, by no 

 means a close relative ; and in some foreign members of this 

 genus the spiracles are lacking altogether, which brings them 

 nearer again to the blue shark. Few of our sharks, in fact, 

 offer less satisfactory material for simple and not too technical 

 description as the porbeagle. In colour it varies between 

 many shades of grey and brown, with a lighter shade of the 

 same beneath. 



Though most familiar in the extreme south-west of the 

 island, the porbeagle is caught on many other parts of the coast, 

 one of the earliest British examples having been figured, 

 described, and even named at Beaumaris. It is not, at any 

 rate in the adult stage, one of the gregarious sharks, though 

 the evidence of the drift-nets sometimes shows that one or two 

 couples may hunt in company. The food that they pursue is 

 probably of the most varied character, including smaller 

 sharks and dog-fishes, herrings, pilchards, mackerel, and squid. 

 The blue shark and tope of our seas have a favourite habit 



