Woodburn .- — Spermatogenesis in certain Hepaticae. 301 
in the earlier, as well as in the diagonal, divisions of the spermogenous 
tissue of Riccia natans. These bodies, which he is not inclined to consider 
as true centrosomes, do not have genetic continuity, but disappear after each 
cell-division, except the last, when they persist in the sperm cells and 
function as blepharoplasts. He finds no evidence of their nuclear origin, but 
considers them as arising de novo with each cell-division. In the formation 
of the spindle, cytoplasmic fibres radiate from the nucleus and converge at the 
centrosome-like body. While the behaviour of this body seems more like 
a blepharoplast than a centrosome, the fact of its occurrence in so many 
cell generations before the formation of the sperm leads to some difficulty 
in determining its nature. 
Escoyez (’07) describes the behaviour of the chromatin and the forma- 
tion of the spindle in diagonal and prediagonal divisions of Marchantia 
polymorpha . Contrary to Ikeno’s observations, no centrosome-like body, 
according to Escoyez, is apparent until during the prophase of the diagonal 
division. Then in each corner of the sperm- mother-cell a darkly stained 
body appears, which will lie at the pole of the spindle. A body of similar 
appearance may occur also in each corner of the cell, which will be in the 
plane of the cytoplasmic division. He found no evidence of the nuclear 
origin of either of these bodies, but states that the body, or corpuscle, which 
occupies the pole of the spindle, persists in the sperm cell and functions as 
the blepharoplast. 
In early divisions of antheridial cells of Fegatella , he found no centro- 
some-like bodies. The last division of the spermogenous tissue was not 
studied. 
Escoyez concludes that centrosome-like bodies are present in the 
spermogenous tissue of Marchantia in the last division only, and that these 
corpuscles are the blepharoplasts ; that they are not true centrosomes, 
functioning secondarily as blepharoplasts, but organs sui generis of the 
antheridial cells. They are the ‘ cilia bearers ’ and play no role in karyo- 
kinesis. If they were true centrosomes they should also be found in the 
earlier divisions. The mere fact that they occupy the poles of the spindles 
does not imply that they take part in the spindle formation. 
In his studies, Schaffner (’08) found bodies, which he called centrosomes, 
occurring in all spermogenous divisions of Marchantia. These bodies, he 
says, persist through the last divisions and function as blepharoplasts. The 
latter are modified centrosomes, and their ontogeny can be traced back 
through the preceding cell- divisions of the antheridium. He does not state 
the origin of these bodies, nor whether they persist during all phases of 
karyokinesis. 
Miss Black, while working on Riccia Frostii , Anst., during the winter of 
1909-10, found no centrosome-like bodies in any phase of the prediagonal 
divisions or immediately after the diagonal division. But at a later stage, 
