298 



Pub. Fuget Sound Biol. Sta. 



Vol.. 2, No. 51 



The sporelings in seawater having a pH value of 8.4 increased 

 from 0.072 mm to 0.224 mm in the first 72 hours. This was an increase 

 of 0.152 mm^ which was a greater increase than occurred in seawater 

 having a pH value of 8.0-8.2. By the eighth day the length was 0.30 

 ram, and by the thirteenth day it was 0.332 mm, an increase of only 

 0.032 mm in five days, while the sporelings in the seawater having pH 

 values of 8.0-8.2 were 0.40 mm long in the same time. Growth seems 

 to be inhibited after about 72 hours in seawater having a higher pH 

 value than 8.2. 



The sporelings growing in seawater having a pH value of 8.6 were 

 living at the end of four weeks. At this time they were 0.24 mm in 

 length, an increase of 0.178. The growth was quite rapid for the first 

 eight days, when it was practically inhibited, and many appeared dead 

 by the eighteenth day. A considerable number of the sporelings became 

 loosened from the slide during the remainder of the four weeks. 



The sporelings growing in seawater having a pH value of 8.8 grew 

 very slowly and life was considered extinct after the seventh day. No 

 growth took place after this time and the sporelings were dark gray 

 instead of brown in color. Many of the sporelings soon became loosened 

 from the slide. The length of the sporeling on the seventh day was 0.08 

 mm. As the oospore is about 0.072 mm in diameter, the sporeling had 

 increased 0.008 mm in length in seven days. For a graphic representa- 

 tion of this increase in length see plate 52. 



The effect of different pH values and temperatures on the size of 

 sporelings as measured by width and length at the end of four weeks 

 is summarized in table 4, from which the following is evident: 



Table 4. Size of sporelings in different p H values and different tem- 

 peratures of water at the end of If. weehs. 



* Dead on 24th day. 



