372 
Notes. 
divides up into a small cellular mass, all of whose cells by a process 
of rounding off become asexual reproductive cells or spores 1 , each 
one of which will produce a Coleochaete plant which will in turn 
produce asexual reproductive cells, gonidia, producing Coleochaete 
plants again. This process goes on for some time making a series of 
similar individuals. 
It is only towards the end of this series that individuals appear 
which bear sexual organs ; or they are produced by individuals which 
survive long enough from the earlier parts of the series, as to be sub- 
jected to conditions favourable for the development of sexual organs. 
The only individual that is quite incapable of sexual reproduction is 
that formed by the growth and division of the oospore. 
Pringsheim considered the whole series of individuals, including 
that produced from the oospore, to be primitively of the same nature ; 
that originally there had been a series of individuals all of which were 
capable of either sexual or asexual reproduction. He then supposed 
that from the rest of the series, the one produced by the division of 
the oospore was differentiated by losing all capacity of sexual re- 
production, retaining only the capacity of asexual reproduction, while 
the rest of the series retained the capacity of both sexual and asexual 
reproduction, the latter being more prominent in the earlier members 
of the series, the former in the later members. 
The individual produced by the division of the oospore Pringsheim 
regarded as homologous with the sporophore of the Mosses, Ferns 
and Flowering-plants, the rest of the series as corresponding to the 
oospore, although not completely differentiated from the generalized 
condition like the sporophore. This view was supported by a 
comparison with some of the Mucorini, in which there is a rudimen- 
tary alternation of generations. To this point I shall presently 
return. 
Leaving out of consideration the Fungi for the present, and 
comparing the life-history of Coleochaete with that of certain Algae 
only, seems to me to lead to a different view of the origin of alterna- 
tion of generations in the cases under consideration. 
For if it is granted, as every one now will grant, that in Coleochaete 
there is alternation of generations ; then it can be shown that there is 
alternation of generations in many other green Algae. 
1 Sachs’ nomenclature in regard to spores and other asexual reproductive cells 
is used throughout : see below. 
