DISTRIBUTION OF SUBSTANCES IN SPERMATOZOON. 25! 



periphery, which becomes thicker towards the connecting region 

 between head and tail, where it constructs a large ring. The 

 central zone is more refractile. It is larger towards the con- 

 necting region and diminishes towards the apex. 1 Almost all 

 transformations of the ring can be seen in fresh spermatozoa; 

 the sensillac amoeboideae show most clearly. The migration of 

 substances can be deduced by seeing the changeable sizes of 

 various parts of the same spermatozoon during the observation. 



In the preceding observations, there is one fact which deserves 

 more emphasis: this is the stickiness of the pointed part of the 

 head, and of the connecting region too. Very frequently, and 

 chiefly in some particular reactions, taken into consideration 

 below, the spermatozoa bunch together, sticking by these two 

 regions. By careful and patient observations of fresh sperma- 

 tozoa, during longer time and in various media, one gets the 

 impression that the spermatozoa eliminate through the point of 

 the head (where really there is an exceedingly minute opening) 

 very small amounts of an extremely sticky substance. 



8. THE EFFECTS OF EGG- WATER ON THE SPERMATOZOA. 



The mutual relations of the various constituents of the sperma- 

 tozoon, being established and knowing the lability of these 

 relations, a large field for studying the topographical changes of 

 the principal substances in various media is opened. I shall 

 limit myself here to one point: the changes which occur in the 

 spermatozoa in egg-water, which might be expected to resemble 

 changes preliminary to fertilization. 



This is the classical phenomenon studied by Lillie. 2 It is very 

 well known at the present time that there is exerted an agglutina- 

 tive action upon spermatozoa by the sea-water in which sea- 



1 Mischer (loc. cit.) noticed the same thing. Ballowitz in Untersuch. n. die 

 Struktur d. Sp. (Fische, Amph. Kept.), p. 249, distinguishes in the head of the 

 spermatozoon two different zones, and he says that in the process of swelling "the 

 internal zone leads." In fact, it alone swells the external substance merely changing 

 its place. 



2 Frank R. Lillie, "Studies of Fertilization. VI. The Mechanism of Fertiliza- 

 tion in Arbacia," 1914, Journ. oj Exp. Zoo/., Vol. 16, p. 523. Frank R. Lillie. 

 "Studies of Fertilization. V. The Behavior of the Spermatozoa of Nereis and 

 Arbacia with Special Reference to Egg-extractives," Journ. oj Exp. Zoo/., Vol. 14, 

 1913. P- 515. 



