322 



ICHTHYOLOGY. 



Classifica- niay be slipt over a stoiU. man easily. The widest jaws 



tion— usually met with are those of Carcharias, Oxtirhina, Selache, 

 Sharks. i Aj , ■ > •/ ■ 



anu Uaontaspis. 



^^"'v'""^ Of the Galeid^, or Topes and Hounds, we have two Bri- 

 tish examples, one the Galetis cants, named by the fisher- 

 men of different localities " Penny-dog" and "Miller's Dog," 

 but more generally the " Tope," an appellation which Artedi 

 says is Cornish. Galeocerdo arcticiis is a northern species 

 that frequents the seas of Feroe, Iceland, and Norway ; an- 

 other species of the same genus inhabits the Indian Ocean. 

 The Mustelus Icevis, or vulgaris of Miiller and Henle, is fre- 

 quent enough on the British coast. Its flat pavement-like 

 teeth indicate crustaceans as its chief food, which they are 

 adapted for crushing. It giveS less trouble to the fishermen 

 than the other Ground Sharks, which are constantly taking 

 his bait or driving away the fishes he is desirous of catching. 

 Its rich diet improves the quality of its flesh, which is con- 

 sidered in the Orkneys to be more delicate titan that of the 

 Sea-dogs or Sci/llii. 



Lajinid^. Of this family the Lamna cornuhica, so well 

 known on the southern coast of England, and the only mem- 

 ber of its own genus, is an example. It is, from its size and its 

 dentition, the most formidable of the Sharks of common oc- 

 currence in the English Channel. One caught in 1834, off 

 the coast of Caithness, and now in the College Museum of 

 Edinburgh, measured eight and a half feet in length and 

 four feet eight inches in circumference. Its teeth are 

 upwards of an inch in length, flatly compressed, thin-edged, 

 but not serrated ; in outline each tooth is triangular, and 

 the older teeth, have one toothlet sometimes at the base on 

 each side. In the upper jaw, the tooth which follows the 

 first two is smaller than them or than the one which succeeds 

 it. In OOT/r/(i«a the teeth near the symphysis are long and 

 strong, like spike-nails, tapering to a ))oint and slightly 

 curved ; anteriorly they are flat, and posteriorly convex. 

 They are the most formidable-looking teeth that any of the 

 existing Sharks possess, but are calculated rather for holding 

 and tearing their victims than for sawing or cutting. Selache 

 maxima is a nortiiern species that frequents the Greenland 

 and Spitzbergen seas, and descends in the summer to the 

 coasts of New Jersey on the American side, and to the 

 British Channel on the European side of the Atlantic. The 

 teeth are comparatively small, and the habits of the fish, as 

 far as known, are not remarkable for rapacity. In the 

 numerous instances in which it has been captured on the 

 coast of Scotland, nothing has ever been found in its stomach 

 but fragments of sea-weed. It attains a large size, growing 

 to thirty-six feet or more, but it is indolent and not very 

 sensible to sliglit wounds. It is often seen lying on the 

 surface of the water with its dorsal fin raised in the air, 

 whence it has obtained the names of Sail-fish, Sun-fish, and 

 Basking Shark. While thus reposing, it may be easily 

 approached by a boat and harpooned. It enters the bays 

 on the northern shores of Great Britain in the months of 

 June and July, sometimes in numbers but more commonly 

 in pairs, and retires on the approach of cold weather. It 

 is a profitable capture, since eight barrels of fine oil have 

 been procured from the liver of a full-grown fish. Sir 

 Everard Home described much of the anatomy of this fish, 

 with the help of Mr Clift who was the operator, bvit Sir 

 Everard was mistaken when he referred tlie supposed Sea- 

 snake, driven on shore in the Orkneys in 1808, to be this 

 species. The enormous length of the Orkney animal, the 

 smallness of its head and of the adjoining vertebra;, still pre- 

 served in the Museum of Edinburgh University, prove it to 

 have been some great cartilaginous fish yet to be made pro- 

 perly known to naturalists. The parts that were saved were 

 described by Dr Barclay in the Transactions of the If erne- 

 rian Society. 



The A/opecins vulpes is distinguished from the rest of 

 the sub-order by the extreme length of the upper lobe of 



Sharks. 



its tail, exceeding that of the body. It is from the resem- Classifica- 

 blance of this fin to the long brush of a fox, that Mr Yarrell tion — 

 ascribes the origin of its appellation of Sea-Fox, a name by 

 which Aristotle makes mention of it, and which has been 

 handed down to us by ./Elian and Pliny. It generally re- 

 ceives the name of " Thresher" from seamen, on account 

 of its attacking the whale, and striking it violent blows with 

 its tail. Mr Yarrell (i., p. 144) gives a lively account of a 

 combat of this kind, in which a party of Threshers, assisted 

 by a Sword-fish, had nearly mastered a whale when the ob- 

 server lost sight of them. The species attains the length 

 of at least fifteen feet ; but its jaws are not constructed for 

 shallowing a prey equal in bulk to that h Inch a Carcharias 

 of equal length would ingulf. 



Cestracions. This family contains only two species, and 

 perhaps only one, for the difference between the Cestracion 

 zebra of Japan and the Cestracion PhiUipi of the Australian 

 seas, hitherto ascertained, are chiefly those of patterns of 

 colour, which are certainly very dissimilar in fishes taken in 

 the two localities. Miillerand Henle considered them to be 

 mere varieties of one species, and it is to be wished that 

 some competent ichthyologist who has an opportunity of 

 seeing recent specimens from both places, would strictly 

 compare one with the other. The genus is one of much 

 interest to geologists, as the fossil teeth of Cestracions are 

 of older date than those of any other existing genus of 

 fishes. The Cestracion received the name of the " Nurse" 

 in Australia, and the Chinese call it " Cat-Shark" or 

 " Kitten-Shark." Specimens of the young are often found 

 in the Canton insect-boxes. 



Hexanclms griseus, one of the Nolidanidce, inhabits the 

 Mediterranean Sea, but occasionally strays to the English 

 shores. The British Museum possesses one taken off the 

 Isle of Wight. 



The Acanthias vulgaris, the spined Dog-fish, is another 

 of the Sharks that is confined to no one district of the ocean. 

 It is found on both sides of the Atlantic, N. and S., 

 in the Mediterranean, and in the South seas. It is very 

 common in the British seas ; and, according to Mr Couch, 

 as q\ioted by Yarrell, sometimes occurs in almost incredible 

 numbers, 20,000 having been taken in a sean, at one time, 

 on the coast of Cornwall. It does much injury to the 

 fishermen by cutting their lines and carrying off their hooks. 



The Hammer-headed Sharks, Zygance or Sphyrna, are 

 very plentiful in the Bight of Benin, and are considered to 

 be more blindly voracious than others, and therefore more 

 dangerous. They may be often seen ascending from the 

 clear blue depths of the ocean like a great cloud. The ex- 

 traordinarily elongated orbits are flexible in the early stage 

 of the fish's development, and in the fcetus are doubled in 

 upon themselves, so that the head occupies less than half 

 the space it would otherwise do ; neither does the head 

 attain its final shape till the fish is grown to a considerable 

 size. These foetal specimens, from their convenient size, of 

 a foot in length or so, are the most common in museums, 

 and have given rise to some misapprehension respecting 

 the true shape of the head of the adult fish ; and as the 

 transverse distance between the eyes becomes proportionally 

 greater with the age of the fish, several nominal species 

 have been introduced into our lists. M. Valenciennes 

 {Mem. duMus.'w.), in a dissertation on this genus, has given 

 the forms of the heads of several; and in the Supplement to 

 Mr Yarrell's British Fishes, an outline of the head of a young 

 specimen of Sphyrna Blochii, co|)ied from M. Valenciennes, 

 and one of an older fish capt\u-ed by Dr Cantor, are placed 

 side by side, and show well the remarkable change of form 

 which age produces, for Sph. Blochii and laticeps are the 

 same species. A female Spit. Zygcena, measuring nearly 

 eleven feet, examined by the active naturalist just named 

 at Penang, contained thirty-seven living young. This 

 species is almost cosmopolitan, having been taken in the 



