ANALYSIS OF HALL OF 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 two 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 XIJI.—The EHchidermata 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 living starfish, 
the fossils of this family, and compare the plan of the leath- 
ery exterior of Holothurians with the delicate plates of the 
Echinus miliaris, 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 Gordonide, 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 X VI.—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 S7- 
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- 
