ANALYSIS OF HALL OP SHELLS. xxi 



abling the animal to accommodate itself to rounded sur- 

 faces. Its shell consists of eight pieces. 



Chapter XII. — Scheveningen, Holland's famous and 

 fashionable resort, has its t^YO villages and its two lives. 

 The character of its people seems invigorated by their hard- 

 ships. Its sand dunes, its sand beach, and its novel bath- 

 ing arrangements are well given in Holland and its Peo- 

 ple, by De Amicis. 



Chapter XIII. — The Echidermata is a spiny family 

 as well as a family of distinction and beauty, all adhering 

 more or less closely to the example and characteristics of 

 their ancient ancestry. If possible, study Jiving starfish, 

 the fossils of this family, and compare the plan of the leath- 

 ery exterior of Holothurians with the delicate plates of the 

 Evil in lis m iliaris, and examine the spines of the latter and 

 their wonderful adjustment. 



Chapter XIV. — In external appearance barnacles re- 

 semble mollusks, in organism they are crustaceans. The 

 changes accomplished in their various stages are explained 

 in works upon zoology. 



Chapter XV. — The Gordon ida>, which were long be- 

 lieved to be singular and gorgeous sea plants, are now known 

 as the home and work of polypi. Some grow in long branch- 

 like extensions, others look like network of jewels. Their 

 relatives are the polypi — creators of the corals. The soft 

 bodies of these builders are uniform in structure and close- 

 ly adhere to their enlarged type — the sea anemone. Ex- 

 amine and compare structure of different corals. 



Chapter XVI. — Storms destroy many shells while oth- 

 ers equally fragile are lifted to places of safety upon the 

 crest of the waves. Some burrow in the sand, as the Si- 

 phonida, and are discovered by the jets of water they spout 

 out when disturbed. Others are moored by cables of their 

 own spinning : these are the byssus spinners, and notches 

 may be observed in shells of this kind allowing of the 

 passage of the byssus, which the animal attaches at will. 

 Borers also excavate retreats in wood or rock, even some- 



