146 



THE PROTOZOA 



substance of the conjugating pronuclei cannot be deduced from 

 observation, and could only be inferred from analogy. In the 

 gamete-formation of Coccidium schubergi, so carefully studied by 

 Schaudinn (99), a large number of male pronuclei are formed 

 simultaneously by local condensations of chromidia thrown off 

 from the nucleus of the gametocyte, which is left behind in the 

 residual protoplasm, with its conspicuous karyosome (Fig. 50) ; 

 in the female gamete, also, the process of reduction appears to 

 consist of a simple elimination of the karyosome (Fig. 75), a process 

 which could be interpreted more naturally as elimination of effete 

 vegetative chromatin than as a process of true nuclear reduction. 

 In the case of Coccidium, as in others that might be cited, it must 

 either be assumed that reduction-processes, in the strict sense of 



FIG. 75. Four stages in the maturation of the female gametocyte of Coccidium 

 schubergi. A, Full-grown macrogametocyte contained in the host-cell ; 

 B, the macrogametocyte is beginning to round itself off and to expel the 

 karyosome from its nucleus ; C, the karyosome expelled from the nucleus of 

 the macrogametocyte has reached the surface of the body and broken up into 

 a number of fragments, which lie scattered in the body of the host-cell or are 

 extruded from it ; D, the macrogametocyte has now become a ripe macro- 

 gamete, having rounded itself off, eliminated the karyosome from its nucleus, 

 and divested itself entirely of the host-cell, n., Nucleus of the gametocyte ; 

 k., its karyosome ; n.', nucleus of the host-cell ; k.', k/, fragments of extruded 

 karyosome. After Schaudinn (99), magnified 1,000. 



the phrase, occur but have been overlooked, or that the method of 

 reduction is one that can only be brought into line with the typical 

 method by theoretical interpretation founded on analogy. 



It must therefore remain an open question, in the present state 

 of our knowledge, whether a process of nuclear reduction strictly 

 comparable to the process seen in Metazoa is essential to the 

 definition of true syngamy, or whether such a process has not been 

 evolved and perfected gradually as a consequence of the sexual 

 process. It is quite conceivable that syngamy may have been 

 at its first origin merely a process of intermingling of chromatin of 

 distinct cell -individuals ; that in this crude and primitive form 

 syngamy would tend to disturb the normal balance of nucleus 

 and cytoplasm, since it would lead to quantitative excess of the 



