226 C. CLIFFORD DOBELL. 
obvious, if we consider a stage, such as that shown in fig. 21, 
Pl. 2. The daughter blepharoplasts (centrosomes) lie at 
either end, united by the axostyle in its early stage of 
development. It clearly corresponds to a central spindle. 
Around it lie the mantle-fibres—never very strongly developed 
—and the chromatin, though never strictly divided into 
chromosomes, in the equatorial plate stage. Later stages in 
the development of the axostyle are fundamentally but stages 
of growth (e.g. fig. 9, 10, etc.). 
It appears to me justifiable, therefore, to say that the 
axostyle is the homologue of the central spindle, 
each being a centrodesmus. 
An almost similar conclusion has been arrived at by Hart- 
mann and Prowazek (25), though in a different manner, and, 
as | believe, from incorrect premisses. The forms considered 
were the trichomonads from the lizard, following Prowazek’s 
description. ‘They say that the axostyle is formed by the 
“ Caryosom des Amphinucleus,” but I can find no foundation 
for this statement. And further, ‘‘ Die vermutlich mit dem 
Centriol in Zusammenhang stehende Rippe (Achsenstab) ist 
eine Art von Centralspindel und geht in die Rippe des Toch- 
tertieres iiber:’? which is in complete agreement with what I 
have just inferred from my own observations. 
Some other interesting comparisons may be adduced in 
favour of this view. Compare, for example, the origin of the 
tail filament 
also a supporting structure—in spermatozoa,! 
by an exactly comparable centrodermosis, as described by 
Gross (59). And this also corresponds with the origin of the 
flagellum and membrane in trypanosomes and allied forms. 
And further, compare this with the origin of the flagella from 
the central spindle in the spores of Noctiluca as shown by 
Ischikawa (61). 
In the remarkably complicated flagellate Joenia, Grassi 
found an organ which seems to be an axostyle. The division 
of this organism has been investigated by Grassi and Foa 
1 Of Pyrrhocoris. This method does not seem to obtain in most 
other sperms. 
