86 



SATUKDAY Lia.'TURES. 



maturity. In nature it is u fundamental principle that the 

 individual should be sacrificed without limit to secure the 

 good and perpetuity of the race, and the principle might be 

 kept in mind to advantage by those who discuss social prob- 

 lems that concern man. 



Fig. 2. — Yoim<^ of American Oyster: A, surface view of "spat" at first swim- 

 ming stage, with' external opening [d) and cilia; B, do., somewhat older, show- 

 ing beginning of shell (s) ; C, dorsal view of same still older, showing shell {s) much 

 increased in size — all highl)- magnified. (After Ijrooks.) 



But to our young oyster. Here you have its figure (2) — a 

 soft, irregularly-shaped object, with numerous feelers or cilia,' 

 by rotating which it swims about quite rapidly. These 

 young are called "spats" or "spawn" by fishermen, and they 

 swim about till they come in contact with some submarine 

 body, on which they settle, when they are known as " blis- 

 ters." They will adhere to any hard, clean object, but not 

 to mud or dirt. No sooner is the young oyster fixed than 

 it begins to elaborate its shell, which is composed chiefly of 

 carbonate of lime. The food of the oyster consists of va- 

 rious minute creatures, such as diatoms, rhizopods, and in- 

 fusoria, wliicli abound everywhere in water or in mud at 

 the bottom thereof. 



You would hardly suppose that this lymphatic mass was 

 endowed with extreme nervous sensibilitv. Yet it will close 



