HIE SHELL-FISH OF THE COAST. 47 



does not much exceed 18 or 20 fathoms. Their 

 food consists principally of minute larvae, infusori- 

 ans, and the lowly-organized plants known as Di- 

 atoms, but they do not refuse either crustaceans 

 or mollusks, provided these be small enough, and 

 even the inorganic earths form part of their nutri- 

 tive material. In a general way they might be said 

 i,o be omnivorous. The principal spawning season 

 about the Chesapeake extends through the months of 

 June and July, but some individuals may be found 

 with spawn throughout almost the entire year. The 

 eggs, which have been estimated to be contained to 

 the extent of 100,000,000 in a single large female, 

 measure about the one-five-hundredth of an inch in 

 diameter, and give birth to active little creatures, 

 the fry, which are early provided with a rudimen- 

 tary shell. It appears that under favorable circum- 

 stances the fry becomes attached within a day after 

 its liberation ; in this condition the oyster young is 

 known as ' spat.' Spawning begins at about the 

 age of one year. The notion that oysters are harm- 

 ful during all but the so-called seasonable months 

 has nothing to support it beyond the fact that in 

 the warmer months the flesh loses in general deli- 

 cacy and flavor. 



A near ally of the oyster is an irregular lustrous 

 shell, about one inch in diameter, which more gen- 

 erally occurs black or bluish-black on our coast, and 

 is known to eonchologists as Anomia (PI. 3, Fig. 

 8). It is rarely found with both valves attached, 

 the valve commonly found being the upper convex 



