EEPRODUOTIVE ELEMENTS IN APUS AND BRANOHIPUS. 273 



while at its apices some of the pseudosomes coalesce to build 

 up the colossal centrosomes. 



Lastly, just as the fusion within the nucleus brought about 

 the massing of the chromatin into a limited number of 

 chromosomes, so also the extra-nuclear fusion operating in the 

 same way upon the sparse staining material of the kytoplasm, 

 without the nucleus ultimately collects this, into chromatic 

 bodies in the angular spaces between the enlarged globules. 

 They first appear as an irregular cloud on the outskirts of the 

 fusion (fig. 23, d), grow enormously in size, and acquire a regular 

 distribution on the cell periphery. They still, however, remain 

 connected one to another and to the inner group of centro- 

 somes by fine threads ; the fact that they thus form, as it were, 

 the nodal points in a net, suggesting the term dictyosome as 

 expressive of this peculiar relation. It will, moreover, have 

 become apparent from the description that there is no genetic 

 distinction between the pseudosomes, centrosomes, and dictyo- 

 somes, and my sole reason for using the two new terms is their 

 successional appearance. 



In thus bringing into prominence the existence in Branchipus 

 of a veritable " Schaumplasm " and its inter-activities, I would 

 observe that I do so with no predisposition to utilise Biitschli's 

 conception of such structure as a fundamental interpretation 

 of some of the phenomena of karyokinesis, either in this or any 

 other case, but rather the reverse. Nevertheless the observa- 

 tion that a foam structure is intimately bound up with the 

 phenomena of karyokinesis on the one hand (even in a single 

 type) must materially enhance the value of Biitschli's ingenious 

 hypothesis that it is sufficient to account for the amoeboid 

 activities of protoplasm on the other. 



A very natural objection to the conclusion I have stated may 

 arise out of the apparent whittling process to which it subjects 

 the centrosomes, resolving these bodies into nothing more 

 than the irregular staining material between the globules of a 

 protoplasmic froth. 



I wish, however, while concluding this part of my paper, to 

 point out that such an objection is only apparent, and not real. 



