this aperture. It is said that the young oyster has but one chance 

 out of one million, one hundred and forty-five thousand, to survive and 

 reach adult life, so numerous are the destructive agencies which sur- 

 round it. To offset this terrible mortality, each oyster lays several 

 million eggs in order that a few may survive to perpetuate the species. 

 Oysters are found in many parts of the world, and the different species 

 vary much in their form and in their mode of life. In the ' cock's comb ' 

 both of the valves are curiously plaited, while another species, the 

 ' tree oyster,' grows on the roots of the mangrove. The common 

 edible oyster sometimes attains the length of a foot, while a Japanese 

 species, Ostrea talienwaniensis, reaches the astounding size of three feet. 



"Distantly related to the oysters is the Anomia, or jingle-shell, 

 which attaches itself by a huge plug or byssus to other objects. This 

 plug passes through a hole, or foramen, in the lower valve, and so tightly 

 does it hold the Anomia to the object upon which 

 it is resting, that its shell becomes molded to the 

 surface of that object. You will note several 

 specimens in this case which are attached to the 

 shell of the scallop, the Anomia having its shell 

 ribbed in precisely the same form as the scallop. 

 In France, this animal is used as an article of food. 



" You have no doubt heard of the ' dancing; 



,, . , , Anomia simplex, one of 



scallop, and here you may see nearly a hundred the "jingle -shells." The 



-I-. < i i rni ! j.i r> / 7 orifice through which the 



dirfcerent kinds. I his iamily, the jrectimace, is com- byssai plug is thrust is 

 posed of rounded shells, many with frills or ribs, ofthe figure. 6 S^n.?"' 

 and nearly all ornamented with beautiful colors. 



Here is one from China, for example, with one valve white and the 

 other reddish brown streaked with white. Unlike the quahog and 

 clam, these animals have no siphon, and the shell is open all the way 

 around save at the hinge. The edge of the mantle is provided with 

 small, round, black eyes. With its foot, the animal spins a byssus, 

 which it extends through a little notch on one ear of the shell near 

 the hinge, and with which it attaches its shell to pieces of seaweed, 

 bits of wood, and other objects. A beach at low water is an inter- 

 esting place, the receding tide having left on the shore, or in little 

 pools, hundreds of these mollusks, attached by the byssus to pieces 

 of seaweed. As one stands gazing wonderingly over the vast fields 

 of yellow sand and green weed, an object will suddenly move through 

 a pool of water with astonishing rapidity, accompanying the movement 

 by a quick, snapping sound. This is the scallop, which is imprisoned 

 in the pool and desires to get out. The movement is effected by rapidly 



73 



