FISHES. 543 



grade in temperature, a torpedo preserved its faculties during five or 

 six hours ; another, which remained during ten hours in a very small 

 quantity of sea-water at a temperature of 10 to 1 1 Cent, and which 

 seemed dead, revived a little when placed in water at 20 Cent., and 

 gave shocks during an hour. If held firmly by the tail, and pressed 

 both above and below by a platinum rod to gather the true electricity, 

 the animal contracts itself violently ; but its movements are not 

 always accompanied by electrical discharges, which demonstrates that 

 the jets of electrical matter are not the result simply of the muscular 

 contractions, but that they are subject to the will of the animal, and 

 evidently given for resisting its enemies, and benumbing its prey. 

 How wonderful and varied are the resources which Nature grants to 

 her creatures in order to secure their existence ! 



The families of the sub-order Squalina are Scyllidce, or Dog-fishes : 

 Carcharidce, or true Sharks ; Zygcenida, or Hammerheaded Sharks ; 

 Lammdce; Galeidce ; Cestraciontidce; Spinacida; and Squatinida. 

 All the species have a lengthened body, merging into a thick tail, 

 pectorals moderate in size, gill-openings on the sides of the neck, 

 and not beneath the body, as in the Rays ; eyes lateral. 



Carcharidce. This family contains the true Sharks. Some species 

 are said to attain the length of twenty and even thirty feet ; but 

 size is not their worst attribute ; they have received, besides, 

 strength and terrible teeth. Ferocious, voracious, impetuous, and 

 insatiable, spread over almost every climate, inhabitants of every sea, 

 and recently not seldom seen on our own shores, the sharks will 

 rapidly pursue every fish, which fly at their approach ; and threaten 

 with their wide gullet the unfortunate victims of shipwreck, shutting 

 them out from all hope of safety. 



The body of the shark is long, and its skin is studded with small 

 tubercles : this skin becomes so hard, and takes so high a polish, 

 that it is employed in the preparation of various ornamental work. 

 This dense resisting coat protects the shark from the bites of every 

 inhabitant of the sea, if there be any daring enough to approach it 

 with that view, 



The back and sides of the White Shark, Car char ius vulgaris 

 (Fig. 361), are of an ashy brown; beneath it is faded white. The 

 head is flat, and terminates in a muzzle slightly rounded. Its terrible 

 mouth is in the form of a semicircle, and of enormous size ; the 

 contour of the upper jaw of a shark of ten yards length being about 

 two yards wide, and its throat being of a proportionate diameter to 

 this monstrous opening. When the throat of the animal is open we 

 see beyond the lips, which are straight and of the consistence of 



