CHARLES G. ROGERS AND ELSIE M. LEWIS. 



other junction of the thermo-couple. The water in the bath was 

 kept in constant and rather rapid motion. The temperatures 

 reported range from 16.00 to 22.15 C. Work was carried on 

 also at higher and lower temperatures, but proved to be less 

 satisfactory on account of the difficulty experienced in maintain- 

 ing a constant temperature for the time required for a complete 

 series of observations. So far as carried, however, the results 

 corroborate the data here offered and also the results previously 

 reported. This statement holds for both sudden and for gradual 

 changes of temperature over short ranges. 



As will be seen from an examination of the data offered in 

 Table II. the temperature difference between the animals and the 

 water in which they were placed was remarkably low. In six 

 out of the eleven cases reported there was no difference deter- 

 minable. Two worms showed a temperature of 0.0084 below 

 that of their surroundings, and one a temperature of 0.0084 

 above that of the water, maintaining this difference for a long 

 time. One worm showed a temperature of 0.042 below that of 

 the water, and one a temperature of 0.084 above. The specimen 

 last mentioned is the only one in the whole series examined which 

 showed so considerable a temperature difference, and seems to us 

 in the light of the results obtained upon the other forms to be an 

 unusual case. 



EXPERIMENTS UPON THE CLAM ANODONTA. 

 The number of animals used in this series of experiments was 

 small, and the work would perhaps have been more satisfactory 

 if a larger number of animals had been employed. In general 

 the results are similar to those obtained in the case of the earth- 

 worm. In every case the adjustment of the animal to the tem- 

 perature of the water in which it was immersed was much slower. 

 This can be accounted for upon the fact that the mass of material 

 was so much greater. Each clam weighed somewhere in the 

 neighborhood of 200-250 grams. The great mass of the shell in 

 addition to the bulk of the fleshy parts of the animal rendered the 

 temperature adjustment slow. The glass-covered junction was 

 inserted into the mouth or pushed in between the visceral mass 

 and the foot. We were not able to determine that one place was 



