OF MASSACHUSETTS. 95 



scallops were obtained. Undoubtedly there are but few places in these 

 rivers where the temperature and other conditions are such that trans- 

 planted scallops can live. As a whole, the region is unsuited for the 

 scallop and no industry can ever be expected. 



(2) Deformity of Shell of Scallops grown under Artificial Condi- 

 tions. Scallops confined under artificial conditions frequently show 

 deformities. In nature, deformities in shell occur occasionally, usually 

 being due to the loss of part of the secreting mantle or by contact with 

 some object. The young " seed " scallops confined in the wire cages fur- 

 nished three types of deformity: (1) a general type, the ratio of width 

 to height being much greater than in the normal " seed; " (2) the thick- 

 ness of the caged " seed " exceeded the thickness of the normal scallop ; 

 (3) many individuals in the cages showed indented shells, angular pro- 

 jections corresponding to the position in which they had rested in con- 

 tact with the wire sides, and numerous other malformations occasioned 

 by their cramped quarters. All these factors operated against perfect 

 work in recording the growth of the caged scallop. 



(3) Growth of Small and Large Scallops of the Same Age. The 

 size of the " seed " scallops of any set vary greatly, but by the time they 

 are ready for market the size is more nearly uniform for scallops under 

 similar conditions, i.e., there is less individual variation. One of the 

 surprising facts noted was that the penned scallops, by the increased 

 rapidity of growth, caught up with the larger before the season was over. 

 In one pen two lots of scallops which on May 1 measured 38 and 46 

 millimeters respectively, by December 1 were each 60 millimeters in 

 height, the smaller scallops having made up the difference of % of an 

 inch, and had a gain in volume of 477 per cent., while the 46-millimeter 

 scallop had only increased 249 per cent, in volume (Fig. 90). In sev- 

 eral cases this fact was observed and substantiated, likewise from 

 measurements of the natural scallops, showing that the scallops which 

 are backward in growth the first year, either from poor location or 

 late spawning, when placed under favorable conditions have a greater 

 potential energy for growth than the larger "seed," and practically 

 make up the loss in the first season by increased gain during the second. 



(4) Individual Variation and Heredity. Each scallop has its indi- 

 vidual characteristics. Take any number of scallops of the same size, 

 no matter how few, and let them grow for a month or more. When 

 measured considerable variation will be found, in spite of the fact that 

 all the scallops had the same advantages and were under the same con- 

 ditions. It is due to the individual variation in the growing powers of 

 the different scallops, such as, e.g., their capacity for feeding or shell 

 secretion, and is primarily the result of either injury or heredity. Indi- 

 vidual scallops have been marked and it has been found that generally 

 a slow-growing scallop will keep the same rate during the entire season, 

 in spite of changed position. 



