310 Wood burn. — Spermatogenesis in certain Hepaticae. 
(Fig. 57). Fig. 58, which is a side view, shows this body developing 
as a cord along one edge of the cell. So far as stages were observed, 
the blepharoplast developed and the nucleus changed in shape and structure 
as in Porella and Marchantia. Fig. 59 A compares very favourably with 
Figs. 18, 19, and 20 of Porella, although the blepharoplast cannot be traced 
throughout its entire course. The rapidity of development, however, com- 
pares with that of Marchantia. The mature sperm (Fig. 60) is somewhat 
larger than that of Marchantia (Fig. 44), otherwise they appear quite 
similar. The cilia arise from nearer the tip of the blepharoplast in Mar- 
chantia and Fegatella than in Porella (compare Figs. 44 and 60 with 
Fig. 24). The cytoplasmic vesicles in the two former differ slightly from 
the latter, and all three differ in size ; but the general form and structure is 
the same in all three plants. 
Conclusions. 
The evidence furnished by these studies seems to warrant certain con- 
clusions. In the first place there is no evidence that centrosomes occur in 
the spermogenous tissue of Porella and Asterella , or in Marcha?itia and Fega- 
tella, as has been claimed by certain investigators. When occasional bodies 
are found in the cytoplasm or the region of the spindle they do not present 
the behaviour or appearance of centrosomes. Miss Black found the same 
conditions to prevail in Riccia Frostii , as did also Escoyez in Marchantia . 
During the last division of the spermogenous tissue of Marchantia and 
Fegatella , which results in the formation of the sperm cells, a darkly stain- 
ing body, as a rule, occupies each pole of the spindle. There is no evidence 
leading one to believe that this body is of other than cytoplasmic (kino- 
plasmic) origin. There are no indications that it arises in the nucleus. No 
radiations except the spindle fibres extend from this body. Van Hook (’00) 
found centrosomes with profuse radiations extending into the cytoplasm in 
dividing vegetative cells of Marchantia. I compared my slides with those 
of Prof. Van Hook, but found that my preparations of the spermogenous 
tissue showed no figures similar to his of the vegetative tissue. I also com- 
pared my slides with those of Prof. Mottier showing centrosomes in 
Dictyota , but found in mine no similar structures. No figures similar 
to those found by Farmer (’ 95 ) in the germinating spores of Fegatella 
and Pellia , and by Farmer and Reeves (’ 94 ) in Pellia , were found. 
Furthermore, there is no conclusive evidence that this body, which 
occupies the poles of the diagonal spindle, persists as an individual in the 
resulting sperm cell. No genetic continuity can be traced throughout even 
two cell generations. Whatever may be the nature of this body, its appear- 
ance and behaviour do not agree with that of a true centrosome in those 
places where this latter organ is found. 
