466 Beard. — Reproduction in Animals and Plants. 
Infusoria. All else has only been offered in order to con- 
vince the reader of the inherent probability of the truth of 
the attempted solution. This is certainly new, and Maupas 
could not have entertained the slightest idea of it. This is 
certain from the general discussion in his memoir. 
Before the close of my remarks on the conjugation of the 
Infusoria, I should like to quote a passage from R. Hertwig 
and express entire agreement with it. As against Maupas 
on p. 214 of his work on Paramecium Hertwig writes : 4 Bei 
den meisten Infusorien copuliren weder sexuell dififerenzirte 
Kerne, noch auch Kerne sexuell differenzirter Thiere, sondern 
gleichwerthige Kerne, welche in gleichwerthigen, aber ge- 
trennt und unabhangig von einander entwickelten Thieren 
entstanden sind. Damit fehlt aber die Basis fur die BegrifTe 
mannlich und weiblich, vollends aber fiir den Begriff Herma- 
phroditismus.’ 
It is doubtless highly hazardous on the part of a zoologist 
to venture an opinion that the botanists may, nay, must be, 
in error in supposing spore-formation to be a later acquisition 
than sexual reproduction. 
We are bound to assume it to be a primitive process, 
which had its origin in the necessity of reduction following 
a conjugation 1 . 
The primitive form of ‘ sexual ’ reproduction or conjuga- 
tion — and by either of these terms may be understood the 
1 Another, and perhaps better, way of stating this would be that an antithetic 
alternation of a very simple kind must be a consequence of even the most primitive 
conjugation in plants also. That a suspicion of an alternation of generations with 
spore-formation is more than justified even in the simplest plants is proved by the 
facts of the conjugation of Closterium , as described by Klebahn. After the con- 
jugation of like gametes, the resulting zygote, i.e. its duplicated nucleus, divides 
twice without resting- phase. Four nuclei arise, two in each cell as there is only 
one fission of the protoplasm of the zygote. As described by O. Hertwig (Die 
Zelle und die Gewebe, pp. 224, 225) ‘ the two nuclei of each (of these cells) rapidly 
acquire a different appearance, the one becomes large and vesicular, whilst the 
other remains small and later on disappears.’ This is strongly reminiscent of the 
‘ pole-nuclei ’ of the Infusorians, indeed, these abortive nuclei must be regarded as 
exactly the equivalents of the latter. The process is, without question, a spore- 
formation with reduction. Of the spores formed two are abortive. Thus here also 
the antithetic alternation would appear to obtain. 
