OF MASSACHUSETTS. 93 



correctly, it was necessary to have some means of confining the scallops. 

 This was done in three ways: (1) pens of wire netting; (2) wire cages; 

 (3) an inclosed body of water, the Powder Hole. Only the first two 

 can properly be considered artificial, as in the Powder Hole the scallops 

 were in their natural environment. The records were taken at monthly 

 intervals, three measurements being taken of each scallop. 



The pens were located at Monomoy Point, Chatham, Nantucket, Mon- 

 ument Beach, Marion, and in the Annisquam and the Essex rivers. The 

 size of the pens ranged from 40 to 400 square feet, either of sufficient 

 height to extend above the average tide, or covered with a netting to 

 prevent the scallops escaping. The posts were made of 2 by 3 feet 

 joists firmly fixed in the soil and placed at sufficient intervals to hold 

 the netting taut. Wire netting (l^-inch mesh) and old seines were used, 

 the greatest difficulty being to secure the bottom firmly, which was done 

 by base-boards and by fastening the netting in the sand with long 

 wooden pegs. (A complete description of the construction of the pens 

 is given in chapter VII.) It is only fair to state here that pens can 

 probably be improved in such a manner that better results can be ob- 

 tained, and many of the difficulties of artificial culture can be eliminated. 



(a) Artificial compared with Natural Growth. For some reason 

 the scallops in the pens do not grow as rapidly as the unconfined scallops 

 in the same locality. This is proved by a comparison of the growth of 

 penned and unpenned scallops in the Powder Hole in 1905, and also by 

 the table of comparative growths in the pens in the various localities 

 during the summer of 1906. In the first case the growth approximated 

 14.30 millimeters for the penned, as compared with 25.04 millimeters 

 for the unpenned, showing a gain of 10.74 millimeters, or 75 per cent. 

 The average growth from five pens was 16.77 millimeters, as compared 

 with 26.29 for the unpenned, showing a difference of 9.52 millimeters, 

 or 56.8 per cent. It seems peculiar that merely limiting the range of 

 the scallop should have this detrimental effect upon its growth. Several 

 explanations are in order: (1) lack of food by overcrowding in the 

 pens; while this is a very probable explanation, as the scallops were 

 much thicker in the pens than without, it does not seem to hold true 

 for the pens which contained but few scallops, as tnese no wise differed 

 from the others; (2) the accumulation of seaweed and other plant life 

 on the meshes of the netting, which prevented the proper degree of 

 circulation; (3) the lessened activity of the scallop as compared with 

 the freedom of those without, i.e., lack of exercise. Probably to no one 

 of these explanations can be attributed the whole cause, but rather that 

 all three are more or less involved. 



This fact, when applied to scallop culture, is important, as the planter 

 would naturally be desirous of at least attaining as good a growth, if 

 not better, than under natural conditions, and yet if he confines the 

 scallops in small pens he is unable to obtain a maximum yield. There 



