TRANSACIONS OF SECTION K, 577 
The Blepharoplast. 
The blepharoplast is a special organ associated with the formation of the cilia 
in motile spermatozoids and zoospores. It consists of a centrosome-like granule, 
often surrounded by radiations. It appears inside the cell in close relation to the 
nucleus, or sometimes at the periphery of the cell. In Polytoma the two cilia 
thus arise froma granule (blepharoplast) at the extremity of the cell. In Aido- 
gonium the blepharoplast arises, according to Strasburger, in the plasma mem- 
brane. Strasburger considers them as kinoplasmic in nature, and thus brings 
them into relation with his other kinoplasmic structures, the centrosome and 
spindle. 
: In Zamia the blepharoplasts appear in each sperm cell on opposites sides of the 
nucleus and at some distance from it. They are large, well-marked, deeply 
stained bodies, with distinct radiations, and might easily be regarded as centro- 
somes. They break up into granules, which come into contact with the nucleus, 
and gradually arrange themselves as a spiral band at the periphery of the cell from 
which the cilia arise. Similar phenomena are observable in Cycas and Gingko. 
Our knowledge of these is largely due to the researches of Webber, Ikeno, and 
Hirase. In the Filicinese, Equisetacesxs, and Hepatice, according to the researches 
of Belajeff, Shaw, Ikeno, and Strasburger, we have similar results. 
Some authors consider that the blepharoplast is a true centrosome, or 
homologous with a centrosome. It has not, however, been conclusively shown 
that it at any period in its history performs the function of a centrosome, or that 
it is derived from one. Further, in many of these plants, if not all, there are no 
centrosomes at any stage in their life history. 
On the whole the evidence is distinctly against the view that the blepharoplast 
is genetically connected with the centrosome. It is more in accordance with the 
present state of our knowledge to consider the blepharoplasts as special structures 
which arise de novo in the cell for the special function of cilia formation, 
The Cenocentrum and its Function. 
In the odgonia of some fungi there appears at an early stage in the develop- 
ment of the cdsphere a dense granular, deeply stainable substance, the function of 
which is unknown. It appears in the centre of the cell, and was first discovered 
in the odsphere of Cystopus (Albuyo) candida. It is probably formed by an 
accumulation of stainable granules or microsomes, It disappears soon after 
fertilisation takes place, and is therefore not a permanent organ of the cell. 
Shortly after its appearance one of the nuclei out of the large number irregularly 
scattered through the odgonium comes into contact with it, and gradually becomes 
more or less embedded in it. All the other nuclei pass to the periplasm, leaving 
this single nucleus as the nucleus of the ovum. The fertilising tube which con- 
tains the male nucleus also grows towards it, and comes close to it to discharge 
the male nucleus upon it. his indicates that it may exert in some way or other 
an attraction, first upon the female nucleus, and secondly upon the fertilising tube, 
thus helping to bring the sexual nuclei together. Stevens suggests that it may be 
of the nature of a dynamic centre, and he gave it the name cenocentrum. It 
may be nutritive in function, and may exert a chemotactic stimulus upon the 
sexual nuclei. 
It does not appear to be actually concerned in the fusion of the sexual nuclei. 
In Peronospora parasitica, for example, it completely disappears before the fusion 
of the nuclei takes place. So far all the views as to its function are purely 
hypothetical. It may be a mere coincidence that it should become associated 
with the sexual nuclei at the time they come together in the odsphere. Its 
function may be totally unconnected with these, From the fact that it stains so 
deeply in nuclear stains, the substance of which it is composed may be of the 
nature of nuclein, and it is possible that it may be due t> a substance secreted by 
the nuclei of the odgonium for some special purpose connectéd with the maturation 
1905, PP 
