200 H. M. WOODCOCK. 



cliroraatin of the troplionucleus becomes arranged in a long, 

 spirally-wound thread. Its centrosome has disappeared. 

 The chromatic thread is next segmented, both by longitu- 

 dinal and transverse divisions, so that four separate tetrads 

 result. Meanwhile the kiuetonucleus has passed inside the 

 trophonucleus, and appears to serve as the spindle for the 

 reduction-divisions of the latter. After the first mitosis each 

 resulting half has, of course, four dyads instead of four 

 tetrads. In the second division of the germinal nucleus these 

 four dyads are split into monads, or single chromosomes, in 



Fig 15. — A ripe megagamete liberated from its host-cell (lying to 

 the left), n = nucleus of disintegrated corpuscle; t = reduced 

 trophonucleus ; h ^ reduced kiuetonucleus ; r.n. = one of the 

 degenerating reduction-nuclei. (After Schaudinn.) 



the usual way. After this the kinetonuclear part resumes its 

 old position outside, but contiguous to, the reduced tropho- 

 nucleus. How, exactly, the kiuetonucleus becomes reduced 

 Schaudinn was not able to determine. The end-result of the 

 process is seen in fig. 15. To the right lies the spherical 

 female trophonucleus (t.), with its four thread-like chromo- 

 somes, and below it the kinetonucleus {Jc.), consisting of five 

 deeply-staining masses, namely, the four chromosomes and the 

 centrosome.' In the middle lie the two reduction-nuclei {r.n.). 



' It is important to note that, in both gametes, the two kinds of nuclear 

 element are present. Hence, on the one hand, neither is the trophonucleus 

 solely female in character nor the kinetonucleus solely male ; and, on the 

 other hand, neither is the former merely somatic, nor the latter purely 

 sexual. 



