I 34 ARTHUR W. GREELEV. 



velopment. The same temperatures and periods of exposure were 

 used as in experiment 4. The results are tabulated as follows : 



PERIODS OF EXPOSURE TO SOLUTION. 



Practically the same result was obtained as with the KC1 solu- 

 tion. The low temperature slows the action of each solution 

 about equally, although the KC1 solution extracted water from 

 the egg and the acid solution affects the egg only through the 

 specific action of the H ion. As in the previous experiments, an 

 even larger percentage of larvae was produced with a low tem- 

 perature and long exposure, than at the temperature of the room. 

 A temperature of 30 C. had the same inhibiting effect as in the 

 preceding experiments. 



Several experiments were performed on the effects of different 

 temperatures upon the process of artificial parthenogenesis in the 

 Amphitrite egg when produced by the specific action of the Ca 

 ion. The following solution was used : 4 c.c. // Ca (NO 3 ) 9 plus 

 96 c.c. sea-water. Results were obtained in general similar to 

 those already described for Arbacia and Asterias, although they 

 were not nearly so uniform. Artificial parthenogenesis occurs at 

 all the four temperatures tried with periods of exposure as short 

 as fifteen minutes, but the optimum period of exposure is much 

 longer at the low temperatures than at the temperature of the room. 



In a previous paper l 1 described some experiments on the 

 effects of an increase in temperature alone upon the unfertilized 

 Asterias eggs. In no case did I get even a segmentation of the 

 egg by an increase in temperature. These experiments were re- 

 peated this summer upon the eggs of A)>i/>/titrite and Asterias 

 with the same result. I modified the experiment in many ways, 

 keeping some of the eggs constantly at a slightly higher tempera- 

 ture than that of the room, while others were returned to normal 

 sea-water after varying periods of exposure to temperatures rang- 

 ing from 27 C. to 35 C. The protoplasm of the Asterias egg 



1 Greeley, American Journal of Physiology, VI., 1902, p. 296. 



