1906] LEWIS—DEVELOPMENT OF RICCIA 125 
SPERMATOGENESIS. 
The development of the spermatozoids has been treated by a 
number of investigators, among them, CAMPBELL (4), LECLERC DU 
SABLON (23), GUIGNARD (14), SCHOTTLANDER (27), and STRAS- 
BURGER (29). It will be observed that mest of these papers were 
published before methods of preparing material for study were so 
well developed as at present. The work of BELAJEFF (1) confirmed 
by that of STRASBURGER (29) shows that the spermatozoid in the 
Hepaticae consists not only of the metamorphosed nucleus but also 
of the cytoplasm. 
IKENO (16) not only confirms the view that the spermatozoid 
consists of cytoplasm as well as nucleus but also discusses the develop- 
ment of the cilia and the homology of the blepharoplast and centro- 
some of Marchantia polymorpha. 
He finds that the body which becomes a blepharoplast in the 
developing spermatozoid appears in the earlier nuclear divisions of 
the antheridium and functions as a centrosome. It is, however, not 
permanent, but appears at the time of nuclear division and disappears 
during the process, so that it is not found in the daughter cells until 
about the time for the formation of the spindles of their division. 
After the last division which gives rise to the cells that develop into 
the spermatozoids, the body does not disappear but remains and 
becomes a blepharcplast. IKENO argues from this that the centro- 
some and blepharcplast are homologous. He has good grounds for 
such an argument in the case of Marchantia polymorpha, because 
centroscmes have been reported also in the vegetative cells of that 
plant, by MorrTrer (24) and by Van Hook (32). In other plants 
which have the blepharoplast, centrosomes are not found, and the 
bedy appears in cnly one or two divisions before the formation of 
the cells which prcduce the spermatozoids. 
MorrTierR (26) in discussing IKENo’s paper raises the question 
whether the bedies which IkENo has figured as centrosomes are in some 
cases more than ordinary granules such as appear in the cytoplasm 
of other cells in which centrcsomes are known to be absent. IKENO 
has pointed cut, however, that the cytcplasm cf these cells is very 
finely granular, there being no other bodies in the cell which bear 
any resemblance to the ones figured as centrcscmes. He also calls 
