IS THE BLEPHAROPLAST A CENTROSOME. 79 
he calls blepharoplastoids, occur in the division preceding that, giving 
rise to the central cell, and according to Belajeff (14) they appear a 
few cell generations earlier, but still in the spermatogenous tissue. It 
is easy to understand why blepharoplasts should occur in all of the 
spermatogenous cells resulting from the division of the central cell of 
the antheridium, as all of these cells may be considered potential 
spermatozoids. While in J/arst/ia 16 spermatids are formed by 
four successive divisions of the central cell, in some other species 
a less number of cells is formed, some of the intermediate divi- 
sions being dropped out. It seems to the writer, from analogy with 
Zamia and Ginkgo, where the blepharoplasts appear in the central 
cell, that they may be expected to occur also in the central cell of 
Marsilia and other ferns with which the central cell of the pro- 
thallum (antheridium) of Zama is supposed to be homologous. It 
will be remembered that Moore found rudimentary cilia developing in 
the spermatozoa mother cells of salamander. All of the intervening 
cells between the central cell and the spermatids being considered as 
potential spermatids, it becomes evident that we should expect bleph- 
aroplasts or their rudiments to be present. The fact brought out by 
Shaw and Belajeff that these bodies apparently appear de novo in each 
cell generation and then at the close of the division disappear in the 
cytoplasm, new blepharoplasts arising meanwhile to function in the 
next cell generation, seems to the writer to lend strong support to his 
claim of the independent nature of the blepharoplast. 
The evidence from the zoological standpoint would seem to entirely 
favor the centrosome nature of the blepharoplast, as the almost unani- 
mous conclusion drawn in recent work on spermatogenesis indicates 
that the axial filament arises from a centrosome which forms the mid- 
dle piece of the spermatozoid. After the exhaustive researches of 
Meves (82), Hermann (55), Moore (86), Benda, Lenhossek, Suzuki, 
McGregor, Paulmier, etc., this fact can hardly be doubted. Wilson 
says, in summarizing the questions of spermatogenesis in animals: 
In reviewing the foregoing facts we find, despite many variations in detail, three 
points of fundamental agreement, namely: (1) The origin of the sperm-nucleus from 
that of the spermatid; (2) the origin of a part at least of the ‘‘middle piece’’ from 
the spermatid-centrosomes; and (3) the outgrowth of the axial filament from one of 
the spermatid centrosomes. 
Wilson (130, p. 170) also concluded, as stated above, that the cilia- 
forming organ in Zamia, Cycas, Marsilia, etc., is to be homologized 
with a centrosome, and the same conclusion is indicated in Henneguy’s 
discussion of the matter (54). It would be presumptuous on the part 
of the writer to criticise these conclusions so far as they relate to the 
question of spermatogenesis in animals, and they must be accepted by 
him as they stand. He feels, however, that he is justified in refusing 
to admit, at least with the present evidence, that this must be taken 
