2<So A. S. PEARSE. 



minutes. One of these animals soon died but the other was in 

 excellent condition four days afterward. Two other animals 

 were heated to 41° C. during two hours and thirty-eight minutes 

 and both of them died, although one continued to contract slowly 

 when poked for two days. The two remaining individuals were 

 heated to a temperature of 37° C. during two hours and forty 

 minutes. Next day they were both in excellent condition and 

 gave good burrowing and shadow reactions. 



In order to test the effect of decreased temperature, beakers con- 

 taining buried individuals were placed in a pail of cracked ice and 

 salt and allowed to remain until the temperature had been suffi- 

 ciently lowered. A beaker containing one animal was placed in 

 the "freezer" and when the temperature had reached + 8° C. 

 it failed to give the shadow response but contracted somewhat 

 when the beaker containing it was jarred. In two hours and 

 twenty minutes the sand was frozen solid and covered over with 

 ice crystals. A thermometer held against the body of the animal 

 registered — .5° C. At this temperature the posterior end still 

 contracted when poked. Twenty minutes later with the tem- 

 perature at — 1.6° C. only a feeble contraction was induced by 

 poking, and after thirty minutes more the whole body was stift 

 and apparently frozen solid. The animal was left an hour longer 

 and became completely covered over with ice crystals. The 

 beaker was then removed, after having been in the freezer four 

 hours and twenty minutes. The animal was found to be dead 

 after the ice thawed. Another beaker which contained two 

 Thyones was introduced into the freezer. Both these individuals 

 were buried in the sand and covered by sea water. The tem- 

 perature was reduced so that the sand was frozen and a thermom- 

 eter resting against one of the animals registered — 2° C. to 

 — 3° C. for two hours and forty minutes. After having been in 

 the freezer three hours and forty minutes the beaker was removed. 

 Twelve hours later both the individuals it contained had cast out 

 the viscera but they did not die and continued activ^e for several 

 days, though they were in poor condition and gave no shadow 

 reaction. Grave (:o5) observed that Cnannaria retracted the 

 whole body during cold weather and Mr. George Gray had in- 

 formed me that Tkyonc buries itself six or eight inches in the sand 



