266 CARL R. MOORE. 



of insemination. 1 This is undoubtedly due to the condition of 

 the egg, produced as a result of the hypertonic exposure- its 

 capacity for fertilization is being gradually decreased. 



We may correlate, it seems, this gradually progressing un- 

 fertilizable condition of the egg that appears as the eggs are 

 allowed to remain in the solution, and the escape of substances 

 from the eggs which also increases as the eggs are allowed to 

 remain for longer times in the solution. One can readily notice 

 an almost entire absence of pigment from many of these eggs 

 while others will show a decided loss of it. Probably also many 

 other substances escape at the same time from the egg, some 

 of which may be absolutely necessary for certain chemical 

 combinations taking place during fertilization and development. 



The type of swimming larvae obtained in such a series of 

 experiments shows also a very beautiful gradient in normality 

 as well as in number. Most of those obtained as a result of 

 fertilization, after a short hypertonic treatment, appear entirely 

 normal, but the percentage of abnormalities increases as the 

 length of exposure to the hypertonic solution before fertilization 

 was lengthened: after an exposure of if hours to 2 hours prac- 

 tically no normal larva? are obtained and the mortality is very 

 high. 



For the higher concentration the curve (b and b 1 , Fig. i) is 

 decidedly different from (a and a 1 ), the weaker one, but yet it 

 is quite characteristic for exposures to such a concentration. 

 The greatest percentage of cleavages from the hypertonic solu- 

 tion alone are obtained in lots, the exposure of which had been 

 thirty minutes or forty minutes in duration while often a small 

 amount of segmentation is induced by an exposure of if hours. 

 But distinctly different from the curve of cleavages when the 

 lower concentration was used is the fact that the curve of fer- 

 tilization (?) follows more nearly that of the hypertonic treat- 

 ment alone. This is especially true when the percentage of 

 swimming larvae is considered. In dishes of inseminated eggs, 

 previously exposed to the stronger hypertonic solution for 10, 



1 The number of cleavages after a two-hour exposure in this experiment is 

 exceptionally high as compared with scores of other experiments for the same 

 length of time. Usually such an exposure is followed by not more than 3 per 

 cent, of swimming larvae but many times swimming forms do not appear at all. 



