630 SUPPLEMENT ON 



The sea-coasts abound with these eggs, and those of the 

 rays, both commonly called sailors' purses. That of the 

 shark generally forms a parallelogram, in the shape of a little 

 pillow of a tough coriaceous texture, more like vegetable than 

 animal matter, of the colour of horn, with a long curling 

 filament issuing from each angle. 



Though on opening these animals, a number of eggs are 

 usually found of different sizes, each pair of them seems to 

 require a separate fecundation from the male, two only being 

 produced at each parturition. When ripe for exclusion, 

 each foetus is coiled up, and attached by a thread-like mem- 

 brane to a sub-oval white substance, and both foetus and 

 attached substance are inclosed in the purse, which is not 

 unlike a pea-pod, but more regular ; the long tendrils from 

 each corner of this purse, slender, tough, elastic, and like 

 Indian grass, seem to be for the purpose of catching hold of 

 fucus, sea-weed, or any like substance, so as to detain it from 

 too much motion in the water; and thus, when the young is 

 born before exclusion from the purse, it is safely preserved 

 till the period for it to quit its domicile arrives. On first 

 quitting the purse, the oval body or egg to which it is at- 

 tached, and by which it is nourished in the foetal state, drops 

 off, and the young shark is obliged to seek his own suste- 

 nance in the ordinary way. 



The Squalus canicula of Lin. is found in almost all seas. 

 Its voracity is extreme, following ships, and seizing with 

 avidity every thing that may fall or be thrown overboard. 

 Fish, however, form its ordinary food, of which it destroys a 

 vast number ; but it will sometimes attack fishermen them- 

 selves, or those whom it may find bathing. Like the feliuae 

 among mammalia, it generally attacks by surprise, in prefer- 

 ence to open warfare, lying in ambush in the mud or weeds 

 for its prey. 



The skin, when dried, forms an article of commerce, and is 



