xviii THE HALL OF SHELLS. 



moUusks tenanting these shells surpass the marvelously 

 contrived houses in which they live. The power of adhe- 

 sion possessed by the Patella and its ability to sustain 

 great weights should be tested by those who have access 

 to seacoasts. Eead Mollusca, their Shells, Tongues, Eyes, 

 and Ears, by Philip Henry Gosse, F. E. S. Examine com- 

 mon garden snails, comparing their eyes with those of the 

 Pecten upon the seacoast. 



Chaptee III. — The extensive use of Purpuras and 

 Murexes in the ancient dying of purples is shown by the 

 little mountains of shells still lying in vicinities where 

 this industry was plied. The coloring matter — but a drop 

 — contained in a veinlike sac. The Purpura the crest of 

 the city of Tyre. Study Tyre, and learn of the caldron- 

 like cavities in the rocks where these shells were crushed. 

 Compare the shells of this family, noting how the whorls 

 of some of these shells are thickened by varices or nodes, 

 indicating rest periods in growth ; also the immense de- 

 velopment of the last whirl in some ; the elongated spines 

 in others. 



Chapter IV. — Observe with a strong microscope the 

 beauty of coil and polish in the most minute shells. 

 Where living specimens can be examined the tenants of 

 these diminutive shells will be found to possess as compli- 

 cated and delicate organisms as those of larger growth. 

 Study sand from any sea beach. Shake the sand and 

 atoms from sponges on sale, then count and examine the 

 treasures you will find. 



Chapter V. — Undine finds a " sea horn " among her 

 shells. It is the shell Neptune's trumpeter is fabled to 

 have used to still the tumult of the sea. Tritonia tritonis 

 used as a teakettle, the operculum its cover. lanthina fra- 

 gilis, preserved through the beating of waves and the 

 grinding of sand, bears its egg capsules beneath a float, 

 and buoyed up upon the tossing seas the delicate creatures 

 are born to the purple. 



The horny operculum of land snails may be seen, and 



