REFORMATION OF THE CRYSTALLINE STYLE 285 



seem to prove conclusively that the crystalline style is formed in the 

 caecum in which it rests. 



That each of the surviving clams had been feeding and carrying on 

 the digestive processes for some time was evidenced by the presence of 

 food in the stomach and waste material throughout the intestinal 

 tract. 



Experiment 8. July 9, 1918 



Twelve clams with crystalline styles removed were returned to their 

 natural environment. The experiment extended over a period of 

 seventy-two days. 



This experiment, with the two following ones, was conducted. in order 

 to determine, if possible, the exact time required for the complete 

 reformation of the crystalline style in this species. 



Result, September 19, 1918. Nine clams survived the operation for 

 a period of seventy-two days, all being at the end of the period in good 

 condition. On opening the style sac proximal of the point of severance 

 it was found in each case that a crystalline style, well formed and al- 

 most mature, occupied the entire tube and, projecting into the stomach, 

 was in actual contact with the gastric shield. In some specunens the 

 crystalline style was closely coiled for a distance of about 10 mm. 

 from the distal extremity, with the rest of the surface smooth, while in 

 other individuals the style was enlarged for a few millimeters from the 

 distal extremity and abruptly narrowed down to a smaller diameter. 

 This thickening of the distal portion of the crystalline style at this 

 stage in its development seems to indicate that material is added to 

 its surface more rapidly in this region. 



In some of the crystalline styles central cores of food material were 

 evident. Digestive processes were being carried on apparently in a 

 normal condition with the stomach and intestinal tract well filled with 

 food and foreign material. 



In all of the surviving specimens the distal, short divisions of the style 

 sacs, separated by the operations, were either filled with mud or were 

 entirely empty, no evidence of the regeneration of material comparable 

 to crystalline style substance being found. 



Experiment 9. July 8, 1918 



Twenty-six clams with crystalline styles removed as in former ex- 

 periments were replanted in the natural bed from which they were 

 taken. The test covered a period of seventy-three days. 



Result, September 19, 1918. Fourteen clams survived the period of 

 seventy-three days and were in good condition on this date. The crys- 

 talline styles in all of these specimens were well developed and in most 

 cases almost mature. The essential characteristics of the crystalline 

 styles of this stage of development were outlined under experiment 8, 

 there being considerable variation, but no uniform advance in maturity 

 over those of seventy-two days. 



Digestion in all of these animals was proceeding in a normal manner. 



