286 CHARLES HOWARD EDMONDSON 



Experiment 10. July 6, 1918 



Twenty-four clams with crystalline styles removed were replanted 

 under normal conditions in the natural bed from which they were 

 taken. The experiment extended over a period of seventy-four days. 



Result, Se-ptejnber 18, 1918. Fifteen of the twenty-four clams sur- 

 vived the operation and were apparently in normal condition. The 

 proximal division of the style sac of each of these clams contained a well- 

 developed crystalline style either completely or nearly completely 

 reformed (figs. 28 to 30). The crystalline styles approaching maturity 

 have been described under experiment 8. One mature style was found 

 among the fifteen, it being identical in shape, diameter, and general 

 appearance with a style from another animal of similar size that had 

 not been operated upon. The regenerated crystalline styles are uni- 

 formly shorter, after the operations, than were the original ones due to 

 division of the style sacs. 



It is shown, therefore, that the crystalline style of Mya arenaria 

 may, under most favorable seasonal and other environmental condi- 

 tions, be completely reformed during an interval of seventy-four days. 



In fourteen of the clams, in this experiment, the short, distal portions 

 of the style sacs, now healed and closed, were filled with mud and for- 

 eign material or entirely empty. In one specimen this blind tube was 

 occupied by solidified, gelatinous material, identical with the substance 

 of the regenerated style. A similar result was obtained in experiment 7, 

 as recorded above. 



Experiment 11. Carried on during the latter part of December, 1918, and 

 the first part of January, 1919 



The crystalline styles were removed from fifteen clams, and instead 

 of returning them to the natural bed they were placed in a refrigerator 

 under a low degree of temperature to be examined at intervals for the 

 reformation of the crystalline style. As has been pointed out above, 

 Mya arenaria may be kept alive out of water, but under low tempera- 

 ture, for a period of approximately fourteen days. 



On examining specimens subjected to the above abnormal conditions 

 of starvation under low temperature for a period of four days, it was 

 found that the severed ends of the style sacs were healed but not closed. 

 By splitting open the posterior border of the style sac the newly formed 

 style was observed as a delicate sheath of mucus, twisted and convo- 

 luted, enclosing a thread of food material, lying on the right typhlosole 

 or, as in one specimen, applied against the left typhlosole (fig. 20). 

 Individuals examined after a period of six days' starvation and at in- 

 tervals up to the fourteenth day indicated that the development of the 

 crystalline style, under these conditions, was practically inhibited after 

 about the fourth day. * 



