30 NATURAL HISTORY. 



Atlantic, and has been taken in the Japanese seas. Tt is sometimes captured in mackerel nets and 

 salmon nets, and has been taken on lines set for haddock. Cuttle-fish, cartilaginous fishes, hake, 

 pilchards, and herrings, form its usual food. It appears to grow rapidly in early life, since it is nearly 

 full grown before the second row of teeth is cut. Large specimens weigh fully eight hundred pounds, 

 but the usual size is a length of four feet, with a body measuring two feet round in front of the 

 pectoral fins. It is eaten in the Mediterranean, and used as manure in England. In the backbone 

 there are 155 vertebrae. 



In the genus Lamna the teeth are lanceolate, but there are not always little cusps at the base, 

 though they are characteristic of the Porbeagle Shark. In that species the third tooth of the upper 

 jaw on each side is remarkably small, and the width of the first gill-opening is equal from its distance 

 to the last. There are specimens in the British Museum eight feet long. 



The genus Carcharodon is known only from a single species which ranges from the Mediterranean 

 to Australia. It has large, flat, regularly triangular teeth, with serrated margins, twelve on each side 

 in the upper jaw and eleven on each side in the lower jaw. Fossil species have teeth which are 

 sometimes nearly eight inches long. The second dorsal fin is placed in front of the anal fin. There are 

 jaws in the British Museum obtained from Australian specimens which Dr. Giinther states to have been 

 thirty-six feet and a half long, and he appropriately quotes this species as the Great Blue Shark. 



THE THRESHER, OR FOX SHARK.' 



This species has acquired the name of Fox Shark from the enormous length of the upper lobe of 

 its tail. The pectoral fins are very large, and the first dorsal fin is large. The teeth are triangular, 

 and are not serrated. It is the only species of its genus, and is chiefly found in the Mediterranean 

 and Atlantic. Specimens caught on the British coast have measured about eleven or twelve feet in 

 length, one-half of which is formed by the tail. The snout is conical. Couch records that a splash 

 of the tail of the Thresher puts a herd of Dolphins to instant flight ; and instances are recorded of the 

 Sword-fish and Thresher combining to attack large Whales. The stomachs of Threshers have 

 generally been found filled v:ith Herrings. It is rarely taken with the line, but is sometimes caught 

 on the west and southern coasts of England in drift nets. The flavour of its flesh has been compared 

 to that of the Salmon. 



THE BASKING SHARK.f 



The Basking Shai'k is one of the largest fishes of the group to which it belongs. It is some- 

 times as much as thirty-six feet in length. The circumference is enormous in proportion to the 

 length. One which had a length of thirty-three feet measured twenty-four feet round. Its weight 

 may be as much as eight or ten tons, and the height of its body above the ground may be eight or 

 nine feet. This fish has the remarkable habit of floating on the surface of the sea and basking in the 

 sun. It is generally seen between June and the beginning of winter ; it abounds on the coast of 

 Donegal, and frequents the west coast of Scotland when the wind is northerly. Westerly winds appear 

 to bring it up the English Channel, and during their prevalence it has been seen, or cast ashore along 

 the southern coast of England. These Sharks frequently swim in pairs, following each other, and the 

 long moving mass has more than once been described as a Sea-serpent. On one occasion the Sea-serpent 

 was supposed to have been cast ashore on the Sussex coast; when examined it was already in an advanced 

 state of decomposition, but was measured by the village schoolmaster, and sketched, and considered to 

 have a length of about seventy feet. Fortunately a few joints of its back-bone were collected, and 

 afterwards examined. They presented all the characters of the vertebrae of the Basking Shark ; and 

 two large individuals lying end to end satisfactorily accounted for the supposed length of that Sea- 

 serpent. The teeth of this Shark, in proportion to its size, are smaller than in any other member of 

 the group, rarely attaining the length of an inch. The gape of the mouth may amount to as much as 

 three feet. These Sharks are remarkable for the large size of the liver, which yields an immense 

 quantity of oil. Couch, quoting from Brabazon's account of the fishei'ies of Ireland, says that large 

 shoals of these Sharks pass annually in April and May to the north along the west coast of Ireland, 

 where they are known as the Sun-fish, and are seen from a distance, about a hundred miles west of 

 Clew Bay, lying motionless on the surface of the water, out of which the large dorsal fin rises like a 



* Alopecias vulpes. f" Selache maxima. 



