446 Wilson . — Spermatogenesis in the Bryophyta . 
(Ikeno 31), Zamia (Webber 73), Ginkgo (Hirase 27), 2V ephrodium (Yama- 
nouchi 76), Marsilea and Onoclea (Shaw 57), Marchantia and Fegatella 
(Escoyez 22), Fossombronia (Humphrey 30). In several cases the blepharo- 
plast is described as arising in the cytoplasm near the nucleus, as in Adian- 
tarn and A spidium (Thom 67), Derbesia (Davis 19), Polytoma (Dangeard 20). 
II. In several Algae the blepharoplast arises by differentiation of the 
plasma membrane (‘ plasmodermale Blepharoplasten ’ of Ikeno). Stras- 
burger (62), as the result of his investigations on the zoospores of Oedo- 
gonium , Vaucheria , and Cladophora , concluded that in these plants the 
blepharoplast was formed from the plasma membrane ( Hautschicht ) ; 
Mottier (47), in the case of Char a , came to a similar conclusion. 
III. In several Pteridophyta and Bryophyta the blepharoplast is 
stated to be identical with the centrosome or to be derived directly from it 
(‘ zentrosomatische Blepharoplasten’ of Ikeno). This view was advanced 
by Belajeff (7-12), who based his opinion on the examination of Marsilea 
and Gymnogramme . It has been strongly upheld by Ikeno (32-5), as the 
result of his investigation of Marchantia polymorpha. Lewis (43) in the 
case of Riccia ) and Bolleter (13) in Fegatella , have come to similar conclu- 
sions. Jahn (36) states that in Stemonitis flaccida the centrosomes function 
as blepharoplasts, the cilia growing out from them while they are still at 
the poles of the spindle. 
From the present investigation it appears probable that in Pellia epi- 
phylla the blepharoplast is derived directly from the centrosome. 
IV. In a few cases the blepharoplast has a nuclear origin (‘ Karyo- oder 
Kernblepharoplasten ’ of Ikeno). In Mnium sp. and various species of 
Poly trichum , J. and W. Docters van Leeuwen-Reijnvaan (40, 41, 42) state 
that the blepharoplast originates from the nucleolus by division. In the 
present investigation it has been found that a similar process takes place in 
Mnium hornum and Atrichmn undulatum . Another instance of the nuclear 
origin of the blepharoplast has been given by Schaudinn (53) in Trypano- 
soma and Spirochaete. 
Up to the present time, the nuclear origin of the blepharoplast has 
been discovered amongst plants only in the Musci. The fact that the pro- 
cess has now been discovered in three genera suggests that it is widespread 
in this group. 
As already described, centrosomes are not present at any of the 
divisions of the spermatogenic cells in Mnium hornum and Atrichum undu- 
latum. In the latter plant, however, a small body is separated from the 
nucleus prior to each division in the antheridium. A similar body is found 
in Mnium hornum at certain divisions only. In a former communication 
(74) it has been shown that during the division of the archesporial cells of 
this plant, no such body is separated, although at the reduction division its 
presence is easily discovered. During the earlier mitoses in the antheridium 
