226 THE LIVING ANIMALS OF THE WORLD 



and ventral, a movement which causes very slight disturbance of the water. The appearance 

 of the dor_\- in these actions is suggestive of suppressed excitement, his e\'es being fixed on 

 his prey. I do not recollect seeing him actually swallow another fish, but luue no doubt that 

 he gets near enough to a sprat, for example, without alarming it, to seize it b\' the sudden 

 elongation of his curious jaws." The way in which these jaws are elongated is admirably 

 shown in the photograph on page 622. 



Passing now to the Mackerel Family, we arrive at a group of considerable importance 

 from an economic point of view. Extremely active, migrating, and predaceous, mackerel swim 

 in shoals and seize their prey with great voracity, hunting merel_\' b}- sight, and snapping at 

 anything moving through the water, especially if it is silvery, like a small surface-fish. The 

 various species differ greatly in size, ranging from the Common Mackerel of about 18 inches 

 long to the giant Tunny weighing nearl\- half a ton. 



Common Mackerel sw^m in vast shoals, or " schools," as they are called, and one half a mile 



wide and at least twenty miles long is on record. Mackerel feed on the young of other fish 



and small lish generally, and, when these are not to be had, on minute crabs and shrimps. 



r ^ They are very prolific, a 



single mackerel laying 

 from 430,000 to 540,000 



TheTuNNlES are 

 amongst the largest of 

 the surface-fishes of the 

 ocean. Abundant in the 

 Mediterranean Sea, they 

 occur occasionally in 

 British waters. For 

 centuries the flesh of the 

 tunny has been held in 

 high regard as food, and 

 it is frequently seen in 

 the Lisbon markets at 

 the present day. The 

 ., flesh, which is as red as 

 beef, is cut up and sold 

 by weight. The BONITO 

 closel)- resembles the 

 tunny, but is a much 

 smaller fish, which preys largely upon flying-fishes, which it follows for long distances. 



Peculiarly interesting are the Sucking-FISHES. The name by which they are commonly 

 known is bestowed on account of the presence of a large oval sucker, placed on the top of 

 the head and extending backwards over the shoulders — an organ formed b_\- modification of 

 the back-fill. 15y means of this sucking-disk these fishes are enabled to attach themselves to 

 shark's, turtles, ships, or any large object floating in the sea. The hold which they obtain 

 is so strong that it is almost impossible to remove them by force. Being poor swimmers, 

 this method of transportation enables them to pass rapidly to fresh feeding-grounds. 



The natives of Zanzibar, Cuba, and Torres Straits are said to employ sucking-fishes in 

 the capture of sleeping turtles, the fish being secured by a ring round the tail, and liberated 

 as soon as a sufficiently near approach to the quarry has been made. About ten different 

 species are known, the bulkiest of which attains a length of 2 feet and a weight of about 

 8 lbs., a longer but more slender species measuring 3 feet. 



Carnivorous, of small size, and feeble swimming-powers, the family of the We.WERS are 

 remarkable rather for their disagreeable qualities than anything else, though at least one 



Phcic !i Rtinhtld Thill, &' Co.] | Lhj„.,r, Lj 



JOHN DORY 



/'; the centre of each stJe ;i u round hlatk ipot surrounded 6y a f}cile yetlotu ring 



