SHARK. 



658 



been produced. Whether this is the ultimate number 

 which they never exceed, or whether the new rows 

 are produced external or internal of the former ones, 

 are points which have not been ascertained, though 

 it is generally supposed that the inner rows are always 

 the last produced. Some have gone so far as to say 

 that the supplemental rows are produced for the pur- 

 pose of supplying any deficiency that there may be 

 in the external or primary row ; but this is not at all 

 probable, as the whole of the rows are in general 

 equally perfect. Whatever may be the number of 

 the rows, the teeth in the inner one have always more 

 of the swallowing character and less of the tearing 

 than those of the external rows ; and there is every 

 reason to believe that the teeth continue increasing in 

 size as the animal itself increases. 



From this armature, and also from its great mus- 

 cular power and the texture of its skin, the shark has 

 few enemies of whom it can be in much dread. The 

 skin of the shark is so hard and rough in the texture, 

 that no animal would be fond of biting it, while it 

 bites and also strikes very powerfully. The great 

 spermaceti whales are the only animals which can 

 master it ; and it makes a powerful resistance even to 

 these. This resistance is not, however, ultimately 

 successful ; for a shark seventeen feet in length has 

 been found in the stomach of one of these whales. 

 There are other enemies of much smaller size, which 

 are perhaps more annoying to the sharks than these 

 powerful whales, namely, various descriptions of 

 entozoa, which infest their alimentary canal. It is 

 probably the annoyance given by these internal tor- 

 mentors which sometimes forces the sharks on shore 

 in great numbers, though single ones often run them- 

 selves aground in the eagerness with which they 

 pursue their prey. Their eagerness for food is so 

 extreme, that they will leap out of the water, Com- 

 merson says, to the height of twenty feet in order 

 to seize a temping bait. The large ones follow 

 the pretty general law of iishes in eating the 

 smaller ones of their own species. Hardly any 

 substance, indeed, comes wrong to them, so that it 

 is animal matter and in mass enough. Seals, fishes, 

 and mollusca are indiscriminately eaten, the last 

 of which of course are only the larger ones 

 without shells, which are so very abundant in the 

 various seas. They, in fact, perform the same office 

 in the water as the more powerful of the carnivorous 

 animals perform on the land namely, that of arch- 

 scavengers ; only as the element in which they dis- 

 play their powers is much more extensive, their 

 powers of motion are far greater both in energy and 

 continuance. As is the case with the predatory 

 mammalia too, the most formidable of them, of which 

 there are several species, or, at all events, varieties, 

 known by the common name of white sharks, are 

 confined to the warmer latitudes. Some of these have 

 the pectoral and dorsal fins pointed, the posterior rays 

 very short, and the terminations concave, and have 

 the colour more inclining to grey than it is in the 

 typical white shark. It is also more or less spotted ; 

 and the tail and caudal fin, and indeed the whole ap- 

 pearance is intermediate between the typical white 

 shark and the genus Scyllium. 



Sharks, though most of them inhabit near the sur- 

 face of the water, are remarkably tenacious of life ; 

 resembling in this respect, and also in the length of 

 time that their flesh will keep, the bottom fishes with 

 bones more than the surface ones. This is, in part 



at least, owing to the different structure of their gills, 

 which prevents the shrivelling and stoppage of the 

 circulation, which are the causes of death. This tenacity 

 of life has caused the sharks to get a sort of romantic 

 credit for qualities which they certainly do not pos- 

 sess. The larger ones are, as we have hinted, apt to 

 swallow the small ones of the same species ; and on 

 opening a large shark small ones have been found 

 alive in the stomach. From this it has been inferred 

 that the mother takes the young into the stomach as 

 a place of safety. But the stomach of a shark is 

 about the least safe place into whieh any animal can 

 get, and whatever substance is conveyed there may 

 always be considered as conveyed for the purpose of 

 being eaten. It is not so much of the white shark 

 that this maternal tenderness is alleged, but of the 

 blue one, which comes into higher latitudes, and is 

 better known. 



THE BLUE SHARK (C. glaucus) is also a formid- 

 able animal, though much less so than the white 

 shark. It is very common in the Mediterranean ; 

 but it appears seasonally on the south coasts of 

 Britain, and occasionally ranges as far as the extreme 

 north. When it appears on our shores it is seldom 

 more than six or seven feet in length, at which age it 

 has three rows of teeth in each jaw. From this cir- 

 cumstance, one would conclude that it is not then 

 nearly full grown ; for the teeth are supposed to in- 

 crease in number, much in the same way as in the 

 white shark ; as the number of teeth is the same in 

 both jaws at this, which may be considered as the 

 middle age of growth, it seems to follow that both 

 jaws get additional teeth at the same rate until the 

 under one has got its complement, and then the far- 

 ther additional ones come in the upper jaw. These 

 extra rows, as it were, which the upper jaw contains, 

 appear to act along with the rough surface of the 

 tongue in the operation of swallowing. 



The teeth of the blue shark differ a little in their 

 form from those of the white one. The sides toward 

 the mesial line are more hooked than those of the 

 other, while, in the cases where there are only three 

 rows, three or four at the middle of the row have 

 more the character of swallowing teeth. The body 

 is longer in proportion to its thickness than that of the 

 white shark ; the snout is also proportionally longer ; 

 and the fins are differently shaped. The first dorsal 

 is not very high ; it is rounded in the fore part ; and 

 very low in the hinder. The second dorsal is small 

 and low. The pectorals are long and falchion-shaped, 

 with their curvature directed backwards. Their an- 

 terior margin originates under the fourth breathing 

 hole, which holes, as in the other members of the 

 genus, are five in number. The ventral fins are placed 

 about midway between the positions of the two dor- 

 sals, and the anal midway between the last dorsal 

 and the caudal. The caudal has the upper lobe 

 much longer than the under one ; and the membrane 

 of a portion of it toward the point is enlarged into a 

 sort of truncated flap. The under part is nearly as 

 white as in the former species ; but the upper parts, 

 the head, the irides, the upper fins, and the upper 

 surfaces of the pectorals, are clear slate-blue. In the 

 young specimens the teeth are very small ; but they 

 become more formidable in the full-grown ones. 



We quote the following notice of it by Mr. Couch, 

 from Mr. Yarrell's second volume. " The blue shark 

 is migratory, and I have never known it to arrive on 

 the coast of Cornwall before the middle of June ; but 



