654 



SHARK. 



afterwards it becomes abundant, so that I have 

 known eleven taken in one boat and nine in another 

 in one day. The injury they inflict on the fishermen 

 is great, as they hover about the boats, watch the 

 lines (which they sometimes cut asunder without 

 any obvious motive)," fishes never have any motives, 

 obvious or lateral, " and pursue the fish that are 

 drawn up. This indeed often leads to their own de- 

 struction ; but when their teeth do not deliver them 

 from their difficulty, they have a singular mode of 

 proceeding, which is by rolling the body round so as 

 to twine the line about them for its whole length ; 

 and sometimes this is done in such a complicated 

 manner that I have known a fisherman give up any 

 attempt to unroll it as a hopeless task. To the pil- 

 chard drift-nets the shark is a still more dangerous 

 enemy, as it is common for it to pass in succession 

 along the whole length of the net, cutting out, as 

 with shears, the fish and the net that holds them, and 

 swallowing both together." 



On the fishing-grounds in the northern parts of the 

 British seas, these sharks are not so destructive, be- 

 cause a stray comes only now and then. When one 

 makes its appearance on the coast, however, it causes 

 much more alarm than the same recurrence does on 

 the coasts of the Channel ; and the report of there 

 being one puts an end to bathing in the sea, at least 

 for a considerable time. It is not probable that any 

 appear of such size as to be capable of swallowing a 

 human body ; but there is no doubt that they could 

 and would inflict terrible bites. The rumour is, how- 

 ever, always less or more mixed up with the notion 

 of the white shark, and this gives it a terror which 

 does not naturally belong to it. 



The time and manner of the coming of this fish 

 into the British seas is a tolerably good means of 

 judging of the movements of those fishes which it 

 follows, as well as of its own movements. It always 

 follows the surface fishes when they shoal toward the 

 land ; and so it must follow them from the warmer 

 latitudes rather than from the deep water. 



The Fox Shark (C. vulpes). This fish is also called 

 the " Thresher," from the use which it makes of its 

 tail as a weapon both of offence and of defence. It 

 occurs occasionally on the British coasts, but it is far 

 from being common. It is a very roaming animal, 

 and is found in higher latitudes than any of the two 

 former species. Its gape is not so wide, or its teeth 

 so formidable in proportion to its size, as those of the 

 former sharks ; but its tail is a most powerful wea- 

 pon, and it is exceedingly bold and voracious. The 

 snout is short and pointed; the body very stout; and 

 the upper lobe of the tail-fin about the same length 

 as the whole body and head. The pectoral and first 

 dorsal are long and strong, and much falcated ; the 

 ventrals are small ; arid the second dorsal and anal 

 little other than mere finlets. Both lobes of the tail 

 are falcate, the lower one having nearly the same form 

 as the pectoral fins, but shorter and very much pointed. 

 The length of the largest specimens which have been 

 found in the British seas has not exceeded twelve or 

 thirteen feet ; and that which is circumstantially de- 

 scribed by Mr. Couch was " ten feet ten inches on 

 the straight line, and ten inches more on the curve ; 

 three feet four inches round where thickest ; solid at 

 the chest; conical from the snout to the pectoral fins, 

 and thick even to the tail, which organ from the root 

 was five feet and a half long, and consequently more 

 than half the length of the body (the head and tail 



included, of course) ; the eye prominent, round, hard, 

 four inches from the snout ; iris blue, pupil green ; 

 the nostrils small, and not lobed ; mouth five inches 

 wide, shaped like a horse-shoe ; teeth flat, triangular, 

 in two or three rows, not numerous ; spiracles five ; 

 pectoral fins wide at the bases, pointed, eighteen 

 inches and a half long. Measured along the curve, 

 from the snout to the first dorsal fin, two feet 

 five inches, the fin triangular ; from the first dorsal 

 to the second, fourteen inches and a half; this and 

 the anal fin small, triangular ; skin smooth ; lateral 

 line central and straight ; breadth of the tail, includ- 

 ing both lobes, thirteen inches ; the upper lobe nar- 

 row throughout the greater part of its length ; and 

 on the lower margin, at four inches from the extre- 

 mity, is a triangular process. Colour of the body 

 and fins dark blue, mottled with white on the belly." 



Fox Shark. 



This circumstantial description, together with the 

 figure, will enable the reader to form a tolerably cor- 

 rect idea of the appearance 'of this curious fish ; and 

 when he does so, he will not fail to see how well it 

 is adapted for the part which it plays in nature. The 

 body is obviously formed for speed and for the work- 

 ing of the tail jointly. The form and power of the 

 pectoral fins and the first dorsal give it a firm hold, 

 on the water at that part ; while the smallness of the 

 fins on the posterior part of the body allow that to 

 give free scope in all directions to the tail. Nor 

 must we overlook the power of muscle, which is con- 

 tinued to the very base of the caudal fin. From the 

 length, strength, and parallelness of the forward fin, 

 the body can swing on them as on an axis ; and as 

 there are three of them, the plane of that axis admits 

 of much variation. When the body of the fish has 

 a hold of the water by means of the long fins, and 

 the tail moves in the air, the force with which it can 

 strike an object at the surface must be very great. 

 " Mr. Couch," Mr. Yarrell remarks, " says it is not 

 uncommon for a thresher to approach a herd of 

 dolphins (Delphini) that may be sporting in unsus- 

 picious security, and by one splash of its tail upon 

 the water put 'them all to flight, like so many hares 

 before a hound." Other authorities say that the 

 thresher is in constant hostility with all the smaller 

 Cetacea; but the " motive," as it is called, is not quite 

 so apparent. That this fish should swallow dolphins 

 is out of the question, for an ordinary dolphin is more 

 than six times the volume of an ordinary thresher. 

 From the one which Mr. Couch describes, as well as 

 from the size and character of the mouth, it appears 

 that the food consists of fishes of small size. The 

 one in question was taken in a salmon-net ; but 

 voung herrings were found in the stomach ; and Mr. 

 C. adds, that it appeared not to be able to cut its 

 way out of the net, as the blue ehark would very 

 readily have done, and nothing is said of any kind of 

 attack made by it upon the salmon, 



