334 



GRACE MEDES 



vigorous than those of the early period of 1915. They were 

 smaller, developed more slowly, and, in the experimental solu- 

 tions, showed a greater divergence from the normal type. The 

 same may be said, though to a less degree, of those raised during 

 the corresponding period of the following summer. The first 

 few hours of slow development were followed by an interval of 

 more rapid growth, and at the age of 48 hours they were of 

 about normal size. Ultimately, however, in all the cultures there 

 occurred a nearly complete readjustment, and at the age of 120 

 hours, the averages of the several periods, in contrast to their 

 variabiUties, showed the least deviation from type. 



The first series of experiments was undertaken for the purpose 

 of determining the effects of dilution and concentration of normal 

 sea-Avater on the developing embryo. 



Plot 2 



In Experiment 1, the following solutions were employed: 



Experiment 1. Plot 2. August 10, 1914 



a Sea-water (control) 



b 94 cc. sea-water + 



c 88 cc 



d 82 cc 



e 76 cc 



6 cc. distilled water 

 sea-water + 12 cc. distilled water 

 sea-water + 18 cc. distilled water 

 sea-water + 24 cc. distilled water 



/ 70 cc. sea-water + 30 cc. distilled water 



g 64 cc. sea-water + 36 cc. distilled water 



Tables 1 to 6 give the standard deviation, mean length, 

 and coefficient of variation for one hundred individuals, four 

 measurements each, and Plot 2, the growth-curves for the anal 

 arms. Figures 1 to 22 illustrate one typical individual from 

 each of the solutions on the various days of the experiment. 



