OXNEKELLA MA1UTIMA. 
535 
(e.g. G-ymnosphaera) is only skeletal in function, and plays 
no part in nuclear division. (This has still to be determined, 
but it is not easy to conceive how a single centroplast could 
act as centrosome to many different nuclei.) The centroplast 
of the Heliozoa is thus closely comparable with the blepharo- 
plast of the Mastigophora — an organ permanently subserving 
a skeletal function to the organs of locomotion (the flagella), 
and in some forms assuming the office of centrosome at 
division, in others playing no part in this process (as in some 
trichomonads and in Copromonas respectively, as I havo 
shown in two earlier papers (1909 and 1908) ). To say that 
either the centroplast or the blepharoplast is the homologne 
of the metazoan centrosome, and to apply the same term to 
all these structures, appears to me, therefore, inadvisable. 
By giving so wide a connotation to the term “ centrosome ” 
we shall effect an economy in words ; but we shall introduce 
a confusion of thought by grouping together, as the same, 
certain structures which are in many ways radically different. 
In the language of the older morphology, I would say that 
the centroplast and the centrosome may be analogous, but are 
not homologous, organs. 
For these reasons, in addition to those based on general 
grounds, I consider that all phylogenetic speculations regard- 
ing the centrosome, based on a comparison of the Heliozoa — 
or any other Protozoa — with the cells of Metazoa, should bo 
viewed with considerable scepticism. Opinions on such matters 
differ, and always will differ; but for my own part, such 
views as those of Schaudinn, and his many followers, on tho 
“ phylogeny of the centrosome,” appear to be mere specula- 
tions which are not only improperly called “ theories,” but 
are even outside the limits of legitimate hypothesis. 
6. Diagnosis of Oxnerella maritima. 
In conclusion I will add a brief diagnosis of Oxnerellf» r 
which will serve at the same time as a summary of the facts 
recorded in previous pages. 
Oxnerella maritima nov. gen., nov. spec. Aplirotho- 
