154 O UF Food Mollusks 



At this age the shell of the clam was quite transparent, 

 and the protruded stomach of its infant destroyer was 

 observed spread out within it. Newly attached oysters, 

 also, as well as those of larger growth, are destroyed in 

 the same manner by starfish of various sizes. They are 

 never too small to escape. 



Professor A. D. Mead has demonstrated the fact, in- 

 teresting both from a biological and economic stand- 

 point, that the growth of small starfish is proportionate 

 to the amount of food that they consume. Beginning an 

 experiment with two starfish of the same age, and with 

 bodies about the size of a pinhead, if one is starved, 

 it may still be living at the end of a month, but of course 

 will not have grown. The other, if well fed, will, in the 

 same length of time, have become large enough to cover 

 a silver dollar. It was formerly supposed that starfish 

 became sexually mature only after a period of six or 

 seven years. It is now known that they reproduce on 

 attaining a certain size, and size, as indicated above, de- 

 pends directly on the amount of food. The result is 

 that a female starfish may, if large enough, begin to ex- 

 trude eggs during its second summer, and many by that 

 time attain the required size. 



Oyster culture would be quite impossible over a large 

 part of the northern field if starfish were left to them- 

 selves, yet to keep down their numbers is a very diffi- 

 cult task. When not excessively numerous in shallow 

 water, the culturist sometimes takes up the larger in- 

 dividuals one at a time on a spear. 



The real damage is done when starfish move together 

 in great numbers, as they often do. Traveling but a 

 short distance each day, a great army of them may creep 

 over a bed, utterly destroying it. In deep water their 



