ON THE NEMATODES OE THE COMMON EARTHWOKM. 631 
The behaviour of the pai’eutal generation in this culture 
affords the strongest evidence for bisexuality that I have yet 
been able to obtain. The evidence is not absolutely conclu- 
sive^ since the males have not actually been seen to fertilise 
the females either in this case or in any other, but it is very 
strong. The refusal of the isolated females of the genera- 
tion to reproduce is additional evidence. But, on the other 
hand, the two females of this generation with which the 
extraneous males were placed still remained unproductive. 
It should be noted that, if the male did in this cultui’e 
actually take part in reproduction, it would appear that a male 
is capable of fertilising more than one female of the same 
genera,tion. 
Culture E. — Eight larvae were taken from the nephridia 
of a freshly killed Lumb . terrestris and isolated in worm 
extract in watch-glasses. Seven developed into females and 
one into a male. Four of the seveu females were kept isolated, 
and the male was placed with the remaining three females. 
On examining the cultures after an unavoidable absence, I 
found that, while the four isolated females had laid only un- 
fertilised eggs (which rapidly disintegrated), the three females 
placed with the male had produced an F^ generation, which 
in its turn had given rise to an Fg generation. The parents 
and the first and second filial genei’ations were all together 
in the same watch-glass, but could be distinguished by their 
different sizes. The F2 generation was larval and quite small. 
In the Fj generation I could see no males. The only male to 
be seen was the parental individual. Those females of the 
Fi brood, therefore, which reproduced probably did so as herm- 
aphrodites, unless fertilised by the parental male, which I do 
do not think probable. 
Eight of the small larvae belonging to theFo generation were 
isolated. All developed into females, nor were any males seen 
among the unisolated remainder. Each of these eight females 
produced an Fg generation. Their mode of reproduction was 
unquestionably hermaphrodite, for they were isolated while 
in the larval condition. 
VOL. 58, PART 4. NEW SERIES. 
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