36 
W. E. AGAK. 
genetisclien Eiern parthenogenetischer G-enerationen findefc 
man genau gleichen Bilder, die sonst als p:u-allele Konjugation 
homologen Chromosomen gedeutet worden (s. die Arbeit von 
Kuhn in aiesetn Heft). Wo bleibt da die Theorie ? ” Kuhn, 
however, himself suggests that there may have been a para- 
syndesis and subsequent separation of the conjugants. The 
case of Lepidosiren greatly strengthens this possibility. By 
missing out the secoud diakinetic pairing and one (the first) 
of the maturation divisions, a condition similar to that found 
in the Cladocera would be arrived at — aud that the con- 
dition of parthenogenesis has been derived somehow from 
the sexual one is, of course, unquestionable. 
Strasburger has made a series of observations on the 
cytology of plant apogamy (i. e. parthenogenesis without 
reduction of chromosomes) which are in accord with these 
views. He finds that in Marsilia Drummondii there is a 
synaptic contraction as in allied sexual forms, in which conjuga- 
tion presumably takes place. The first peculiarity appears in 
diakinesis, in that some of the nuclei are diploid instead of 
the expected haploid, and some intermediate. He interprets 
the diploid condition as due to separation of the ex-con jugants, 
which is also borne out by the comparative sizes of the 
diakinetic chromosomes in haploid and diploid nuclei. In 
Elatostema acuminata there is a synaptic contraction, 
but this resolves itself into a resting network again, and then 
ordinary somatic division follows. In E. sessile and 
Wikstroemia indica he finds no sign of synaptic con- 
traction in the prophase, and takes this as proof that there is 
no conjugation of chromosomes. 
If it be permitted to speculate from the facts just recorded, 
it is tempting to look upon the relation of parthenogenesis to 
chromosome conjugation as follows. 
In parthenogeuetic reproduction the physiological con- 
jugation of the chromosomes (parasyndesis) is retained 
(Cladocera, Marsilia) but the ex-conjugants separate 
entirely as in Lepi dosiren . Unlike what happens in this 
animal, however, they do not pair again, and in correlation 
