this family, furnishing as it does the beau- 

 tiful pearls of commerce. These animals 

 are found at Madagascar, Ceylon and 

 other parts of the Indian Ocean, several 

 hundred tons being imported into Europe 

 annually. These pearls are formed by 

 some irritating substance, as a grain of 

 sand or some parasite, getting in between 

 the shell and the animal, or lodging in 

 some soft part, which causes the animal 

 to cover it with pearly matter to prevent 

 irritation. The shells also furnish a con- 

 siderable part of the ''mother-o'-pearl" 

 which is so largely used for ornamental 

 purposes. The Margaritifera radiata, fig- 

 ured on our plate, is a member of this 

 family. 



The scallop is an object well known to 

 the tourist visiting New England sum- 

 mer resorts, who has reveled in ''fried 

 scallops." The family to which this be- 

 longs (Pectinidae) is composed of round- 

 ed shells, many with frills or ribs and 

 nearly all ornamented with beautiful col- 

 ors. Unlike the animals which we have 

 been considering, these mollusks have no 

 siphons and the shell is open all the way 

 around save at the hinge, and the edge 

 of the mantle is" provided with little, 

 round, black eyes. It is an interesting 

 sight to observe a beach at low water, the 

 receding tide having left on the shore or 

 in little pools of water hundreds of these 

 mollusks, attached by a byssus to bits of 

 sea weed. As one is gazing wonderingly 

 over this vast field 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 which desires to get out. The move- 

 ment is effected by rapidly closing and 

 opening the two valves of the shell, there- 

 by causing a clicking sound. The noise 

 of several hundred of these shells open- 

 ing and closing and the sight of as many 

 scallops with strings of sea weed attached 

 to them, shooting through the water, 

 looking not imlike a comet with a lon^ 



tail, is quite bewildering. In Europe, the 

 scallop is considered quite a delicacy and 

 several tons are gathered annually. One 

 species (Pecten jacobaeus) has been dig- 

 nified as a badge of several orders of 

 knighthood and it was also worn by pil- 

 grims to the Holy Land a good many 

 years ago. It was called "St. James' 

 Shell." 



The most common shell to the layman 

 is the oyster (Ostrea virginica), the culti- 

 vation of which occupies the attention of 

 a large number of men and the invest- 

 ment of considerable capital. The oyster 

 is free and active when young, but be- 

 comes attached to some submerged ob- 

 ject early in life. Oyster culturists take 

 advantage of this habit by erecting poles 

 in the water to which the young oysters 

 attach themselves. The shells of the dif- 

 ferent species of oyster are not generally 

 of much beauty, but a related family, the 

 Spondylidae, or spiny oysters, are among 

 the most beautiful of bivalves. In this 

 family the shell is ornamented by many 

 long spines and frills, and the colors are 

 different shades of red, yellow and pink. 

 The most beautiful species are found in 

 the Gulf of California. 



The space at our command is far too 

 limited to adequately discuss the many 

 curious and interesting animals which 

 make up the class Pelecypoda. Much 

 might be said of the Solen or razor-shell, 

 with its curious foot which is so great a 

 help in digging burrows ; of the Pholads, 

 which perforate and make burrows in 

 clay, wood and even in the hardest rock ; 

 and of the strange Teredo or "ship- 

 worm," with a long, worm-like body 

 which bores into ships, wharves and any 

 wooden object within reach. But enough 

 has been written and pictured to show the 

 reader that the unpretentious clam, mus- 

 sel or oyster and their relatives have 

 many interesting habits, are encased in 

 beautiful shells, and that some species are 

 of great economic importance to man. 

 Frank Collins Baker. 



