cases the veliger may recover after falling a short distance, or 

 it may fall to the bottom and remain quiet for some time. The 

 response to disturbance, which is the usual response of lamelli- 

 branch veligers, has been taken into account by Mead and 

 Barnes (i8) who have devised a trap whereby quantities of 

 the veligers of the soft-shelled clam, Mya arenaria, can be col- 

 lected and reared without trouble to such a size that they may 

 be used as seed in stocking clam ground. 



The embryos of most lamellibranchs usually remain as veli- 

 gers and swim about freely for a number of days, or even for 

 some weeks. The embryos of Pecten were kept alive for only 

 five days. Weather and an unsatisfactory place to work inter- 

 fered with proper care and they were apparently weakened by 

 starvation. This difficulty could probably easily be overcome, 

 as in other cases, by putting them in vessels of sea water in 

 which cultures of the diatoms that supply the greater part of 

 their natural food have been started, but cultures could not be 

 started at the time, and there have since been no opportunities 

 to return to the scallop grounds during the breeding season. 

 The young of Nucula proxima reared from eggs, have been kept 

 alive for eleven months in a small jar of sea water in which a 

 small quantity of mud from the bottom had been placed after 

 straining it through silk bolting cloth to remove forms that 

 might be enemies. 



Many fishermen report having seen the young scallops 

 attached to shells by means of threads during the early winter. 

 In a few cases small Anomia were brought to me as young scal- 

 lops, but most of the fishermen to whom these were shown did 

 not accept them as young scallops. Their descriptions of young 

 scallops were in some cases quite minute, and apparently accu- 

 rate, and in all such cases the scallops were said to be attached 

 by threads. Pecten irradians is known to attach itself by a 

 byssus in the young (24) and even in the adult stage, and it is 

 very probable that the young of the giant scallop attach them- 

 selves in the same way. If so, when the veligers settle perma- 

 nently to the bottom, they must find something on which to attach 

 themselves in order to keep from being destroyed. If this is 

 true, the absence of suitable material for this purpose may be 

 the reason that many of the old grounds, especially the shallow 



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