288 CARL R. MOORE. 



with initiation of development have produced an environment 

 in which the reaction between a spermatozoon and an egg has 

 been rendered impossible. Spermatozoa enter the eggs in com- 

 paratively large numbers but the eggs are not fertilized. 



In the shorter exposure to hypertonic sea-water many eggs do 

 react with a spermatozoon but since these are conditions in 

 which a very small percentage of eggs segment and a still smaller 

 percentage reach the swimming stage after the hypertonic treat- 

 ment, the observations are interpreted as indicating an effect 

 of the hypertonic solution below the optimum exposure for the 

 initiation of development and as a consequence the eggs have 

 experienced but little change from the normal condition; the 

 exposure did not lead to the initiation of development, therefore 

 the eggs still possess their capacity for fertilization. That this 

 lack of a capacity for fertilization is one that is gradually de- 

 veloped as the exposure to the hypertonic solution is increased, 

 is one of the factors that indicates the quantitative side of 

 fertilization. After a short exposure, polyspermy, in which all 

 sperm seem to have a part, is the general rule; a more pro- 

 nounced effect of the hypertonic sea-water results in a greater 

 number of sperm entering the egg, some showing very weak 

 asters, others being only slightly swollen, while yet a more decided 

 influence may create an environment within which the sperma- 

 tozoon is not only inactive but also it may even undergo dis- 

 integration. \Yhatever changes have resulted from treatment 

 with hypertonic sea-water, spermatozoa that gain entrance to 

 eggs that have been exposed to optimum conditions for seg- 

 mentation, or that have been decidedly over-exposed, do not 

 meet with an environment that will permit of a reactivation of 

 the egg. 



This degeneration of spermatozoa in a non-reactive egg en- 

 vironment calls to mind essentially similar conditions, en- 

 countered normally, in the fertilization of meroblastic eggs such 

 as the pigeon egg described by Blount ('07). Polyspermy in 

 meroblastic eggs appears to be normal but the accessory sperma- 

 tozoa, after the environment has been changed by reactions 

 within the egg set up by a reaction of the egg with the successful 

 spermatozoon, are repelled peripherally and degenerate and 

 disappear. 



