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CLIFFORD DOBELL. 
discovered an important fact upon which this homology could 
be based. 1 
Now the heliozoon studied by Sassaki (Gfy mnosphsera) i& 
multinucleate, though it possesses but a single centroplast ; 
and he was unable to demonstrate that this organ plays the 
part of a centrosome during the nuclear divisions. To this- 
extent, therefore, the suggested homology of centroplast and 
centrosome remained unsupported by facts. 
This deficiency was soon made good. In a brief but 
memorable paper, published in 1896, Schaudinn (1896a) 
described the division of Acanthocy stis aculeata, a 
heliozoon possessing a centroplast and a single nucleus. 
“ From this brief account/’ he says, “it will, I think, be clear 
that the nuclear division in the heliozoon investigated takes 
place in essentially the same way as the typical mitosis of a 
metazoan cell, and that the central granule [= centroplast] 
corresponds to the centrosome of the metazoan cell.” Schau- 
dinn published only six figures of division stages in Acan- 
thocy stis, leaving many gaps which he promised to fill in his 
full account, which was never published. He stated further 
that he had observed similar phenomena in Acanthocy stis 
turfacea, A. myriospina, Raphidiopliry s, Sphasras- 
trum, and H e t e r o p h r y s . The division of all these forms is 
still unknown — or, at least, undescribed ; and no full account of 
the division of Acanthocy stis aculeata has ever appeared. 
To my knowledge, only one partial confirmation of Schau- 
dinn’s statements has hitherto been published. I refer to 
Zuelzer’s description of Wagnerella (1909). Of several dif- 
ferent methods of nuclear division described by the authoress 
in this peculiar heliozoon, there is one in which the cen- 
troplast appears to behave like a centrosome. 2 But although 
1 Another Japanese zoologist — Watase— put forward the same sug- 
gestion in 1894. In the same year, also, Heider demonstrated the 
centroplast of Raphidiophrys — previously described by F. E. 
Schulze — and emphasized its resemblance to a centrosome. Both 
these workers, however, knew beforehand of Sassahi’s results. 
2 I refer to the multiple division of the “ head ” of the organism, 
whereby a brood of young is formed. I do not consider the other 
