94 INLAND FISHERIES. 



and Buzzards Bay probably extends tliroug-li May and Jiine into 

 July. Beginning my observations late in June, I have not been 

 able to determine its limits with any certainty. After the free 

 swimming larval period, the young clams attach themselves by 

 means of a byssus, which is produced from a byssus gland in the 

 foot. Attachment is made to various bodies in the water, but 

 chiefly to the filaments of Enter omorjiha, a green seaweed grow- 

 ing near the shores. Clams may be found so attached from the 

 latter part of June to the first of August. They are to be found 

 in certain localities in immense numbers. The attached individuals 

 measured varied in leng'th from A millimeter to 7 millimeters. 

 The shape of the smaller individuals difters greatly from that of 

 the adult in being much more rounded, with umbones widely 

 separated laterally. As they become older, they gradually assume 

 the outline which characterizes the adult, but in so doing the 

 umbones come to be situated relatively far forward and then 

 again move back toward the middle of the shell on the dorsal side. 

 This shifting in the relatative position of the umbo is due to a 

 more rapid growth of the posterior, and subsequently of the 

 anterior ends of the shell. 



In the smallest forms examined, the mantle folds Avere in con- 

 crescence ventrally. The foot is relatively greatly developed, 

 extending over the entire ventral side of the visceral mass. The 

 siphons have the general characters of those in the adult, but they 

 are filmy, and may be retracted within the shell with very great 

 quickness. 



Clams of all sizes are apparently freeing themselves from their 

 attachment on the weed. The byssus is cast off, and the creature 

 climbs about from one filament to another by means of the foot, 

 sometimes reattaching, sometimes falling free from the weed to 

 the bottom. In the sand, unless it be excessively fine, individuals 

 less than 2 millimeters in length are rarely able to cover them- 

 selves, though they always make the attempt. Those 5 or 6 

 millimeters long are apparently able to burrow beneath the surface 

 of any clam shore. 



