I5O T1IURLOW C. XELSOX. 



during the attachment period should give interesting information 

 as to the prevalence of this type of behavior. 



SUMMARY. 



Full-grown larva? of the oyster shortly before attachment move 

 over an appreciable area of solid surface testing it out with the 

 foot. 



Actual attachment is preceded by circling movements, the 

 larva finally coming to rest with the left valve held in contact 

 with the substratum by the foot. 



The suggestion of Stafford, 13, that the foot is the organ of 

 attachment has been confirmed by direct observation. The use 

 of the foot and of the mantle during fixation is here described. 



The circling movements of the larva while crawling over a 

 substratum not only aid it in obtaining a favorable foothold, 

 but probably are also instrumental in producing a fairly even 

 distribution of the spat. 



CITATIONS. 

 Belding, D. L. 



'10 A Report upon the Scallop Fishery of Massachusetts. The Commonwealth 



of Massachusetts, Boston. 

 '12 A Report upon the Oyster and Quahog Fisheries of Massachusetts. The 



Commonwealth of Massachusetts, Boston. 

 Brooks, W. K. 



'79 Abstract of Observations upon the Artificial Fertilization of Oyster Eggs 

 and the Embryology of the American Oyster. Am. Jour. Sci., New 

 Haven, Vol. XVIII. pp. 425-427. 



'80 The Development of the Oyster. Studies from the Biol. Lab. Johns Hop- 

 kins Univ. No. IV., pp. 1-106. Baltimore. 

 Crozier, W. J. 



'21 Notes on Some Problems of Adaptation. 5. The Phototropism of Lima. 



BIOL. BUL., Vol. XVI., No. 2, p. 102. 

 Field, I. A. 



'09 The Food Value of Sea Mussels. Bull. U. S. F. C., Vol. X XI X., p. 87. 

 Huxley, T. H. 



'83 Oysters and the Oyster Question. Eng. Illus. Mag., Oct. and Nov., pp. 



47-55, 112-121. 

 Jackson, R. T. 



"88 The Development of the Oyster with Remarks on Allied Genera. Proc. 



Bost. Soc. Nat. Hist., Vol. X XIII., p. 531. 



'90 The Phylogeny of the Pelecypoda. Mem. Bost. Soc. Nat. Hist., IV., p. .277. 

 Kellogg, J. L. 



'99 ( )bservations of the Life History of the Common Clam, Mya arcnaria. 

 Bull. U. S. F. C.. 1899. 



