BULLETIN OF THE UNITED STATES FISH COMMISSION. 287 

 OBSERVATIONS UPON OYSTER SPAT AT WOODS HOLL, MASS. 



Iii the early part of the month of August my attention was called to 

 a number of wooden buoys lying on the beach near the light-house es- 

 tablishment at Woods Holl, and which had been taken from the upper end 

 of Buzzard's Bay, near Cohasset. These wooden buoys were replaced by 

 others during the early part of July. Upon examining the surfaces of 

 a number of those which had been removed from their former position, 

 it was found that they were covered with a remarkable "set" of young 

 oysters ranging in size from one-ninetieth to one-eighth of an inch. In 

 some cases as many as twenty-live young oysters might have been 

 counted on a surface of one square inch. Every available clean sur- 

 face was covered more thickly thau I had ever observed anywhere in 

 either the Chesapeake or Chincoteague Bays. It was evident that the 

 attachment of spat in this case would have been very great in that 

 vicinity had there been an abundance of collectors placed in position 

 in the early part of the month of July or the latter end of June, the 

 time which seems to be the most important period at which to place 

 collecting apparatus in position, as shown by my observations in Chin- 

 coteague Bay, where I am satisfied that little or no spat caught on any 

 sort of collecting apparatus previous to the 1st of July, although oys- 

 ters in the vicinity may have been spawning much earlier. 



This point was determined by the following method : Upon examining 

 the shells and old oysters in Chincoteague Bay, about the end of June, 

 I soon became convinced that all the young oysters then visible be- 

 longed to the set of last season. Two facts served to prove this ; the 

 first was that the larval shell was eroded or eaten off of the beaks of 

 the spat shells by the carbonic acid in solution in the water. It was 

 also evident that these young oysters had made a second growth which 

 belonged to this year, because a distinct offset or line indicating as 

 much could be detected on the outside of the upper valve of every 

 specimen which was examined. These data serve to finally fix the ap- 

 proximate time at which the set of spat occurs in the latitude of Chinco- 

 teague Bay. But it is evident that this time is somewhat later in Buz- 

 zard's Bay, on the coast of Massachusetts, from the fact that the spat 

 observed in that neighborhood averaged much smaller than that from 

 the more southern waters alluded to above. 



THE SET OF SPAT IN BUZZARD'S BAY. 



During the second week of August, in company with Vinal N. Ed- 

 wards, I made a trip on the steam-launch from Woods Holl to the head 

 of Buzzard's Bay to examine the set of spat in that region, having been 

 encouraged to do so by what I had witnessed on the buoys brought in 

 from the neighborhood some weeks before. Going to a point of land 

 covered largely by coarse gravel, we found that a planter had sown a 

 considerable area with clam and oyster shells. It was ascertained that 



