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somes”. The nuraber of the latter dirainishes before fertilization, and 
Gayet believes, but is not certain, that their number at the time of fertiliza- 
tion is constant for the species. He notes that in many mosses the ventral 
canal cell is often almost as large as the egg, an Observation that has been 
made also by Goebel (1882, 1898) and Holferty (1904). Gayet thinks 
that the ventral canal cell of Ephemeruni is capable of fertilization, in 
analogy with phenomena of this nature which he reports liaving observed 
in Marchantia. The antherozoids of Fissidens incurvus enter the arclie- 
gone in great numbers, but only one penetrates the egg, approaching the 
egg nucleus and assuming first a crescent, then a spherical shape. The 
thin “bandelet” of cytoplasm on the periphery of the antherozoid fuses 
with the egg cytoplasm, and the male nucleus with the female nucleus. 
The male nucleus acts as a center of attraction, gradually drawing to 
itself the four chromosomes of the female nucleus. Gayet also describes 
the penetration of the egg of Bryuni capillare by the antherozoid, and 
figures an egg of this species containing two nuelei, of which the smaller, 
somewhat crescent-shaped, is apparently derived from the antherozoid. 
Holferty (1904) figures, verv diagrammatically, several mitotic 
figures in the developing archegones of Mnium mspidatum. 
The Leeuwen-Reijnvaans (1907 1) believe that in the division 
of the central cell of the archegone of Polytrichm, a reduetion in ehromo- 
some number occurs, similar to that described for the last division in the 
antheridium. The egg and ventral canal cell, equal in size and containing 
three chromosomes each, then fuse; the cell so produced fuses in turn with 
two antherozoids, each having three chromosomes, the final result being 
a cell with twelve chromosomes — four long, four of medium length, and 
four short — which agrees with the conditions found in sporophyte cells. 
Centrosomes of unknown origin appear in the egg after fertilization. 
Relativelv few observations have been reported upon the cytology 
of the vegetative structures or of spore formation in mosses. De Wilde- 
man (1893) studied the processes of nuclear and cell division in living 
rhizoids of mosses. He figured -with some clearness equatorial plates and 
anaphases, and stages in cell plate formation. The long axis of the spindle 
at first coincides with that of the cell, but its position is in many cases 
shifted later, so that ultimately the new partition wall is more or less 
oblique to the wall of the mother cell. 
von Mohl (1833) described for several Bryales the formation of four 
spores inside each spore mother cell; the spores have oily contents and 
