282 CARL R. MOORE. 



general characteristics. In lot AX 5 however some of the sperm 

 heads are slightly swollen but are not associated with astral 

 radiations and still others are surrounded with weak radiations. 

 Many cases are encountered in which the egg nucleus has broken 

 down into chromosomes, dispersed along the rays of a unipolar 

 spindle, formed by the egg, as a result of the hypertonic treat- 

 ment; and at the same time several sperm nuclei may lie un- 

 changed within the cytoplasm of the egg. 1 In AX 6 most of the 

 eggs have almost completely lost their capacity to react with a 

 spermatozoon. The majority of the sections show the sperm 

 heads entirely lacking an aster, but many asters produced by 

 the effects of the hypertonic solution are present and are very 

 definite. The reaction between the egg and sperm is largely 

 negative. In numerous sections the physiological changes within 

 the egg cytoplasm have not only prevented changes characteristic 

 of normal fertilization, but they are even of such a character 

 as to cause the disintegration of sperm heads. Fig. 3 is a section 

 of such an egg and shows one sperm head yet unchanged but 

 several others are undergoing dissolution. Other sections show 

 another type of disintegration which is characterized by a 

 swollen vesicle about the sperm head which is breaking apart 

 and stains very faintly with iron-ha?matoxylin. 



2. Insemination Subsequent to an Exposure to the Stronger Solu- 

 tions. 



The examination of sections of eggs of the following experi- 

 ment serves to give a general understanding of the incapacity 

 for fertilization, after eggs have been exposed to the stronger 

 solution of hypertonic sea-water. 



Experiment : 



4:30 P.M. Eggs collected, washed three times. 



5:10 P.M. Transferred to hypertonic sea-water (50 c.c. sea-water + 16 c.c., 

 2\ m. NaCl). 



Eggs transferred at intervals to sea- water and divided into two lots X and Y. 

 Lot X remains standing without further treatment. Lot Y inseminated immedi- 

 ately after return to sea-water. Eggs were removed from each lot at definite 

 times and preserved as given in Table IV. 



1 See Wilson, '01, and Kindle, '10. 



