ox THE NEMATODES OP THE COMMON EARTHWOEM. 629 
duced yoaug. Botli broods grew up into females (= Fj 
generation). No males were produced. One young female 
was isolated in worm-extract while still larval. It matured 
and reproduced, but both it and its offspring died immediately 
afterwards. In this culture the isolated female of the F^ gene- 
ration nnqnestionably reproduced without being fertilised by 
a male, for not only were there no males in the brood from 
which it was taken, but it was still larval when isolated. 
Culture B. — Two larvae were removed from a nephridium 
and isolated in watch-glasses with peptone. Both developed 
into females, which matui-ed and propagated. A series of 
about eight generations was produced. (The exact number 
was not recorded.) Amongst all the offspring of the various 
generations no males were found. The females of this culture, 
therefore, like the isolated female of the first filial generation 
of Culture A, propagated without any males being present to 
fertilise them. Spermatozoa were distinguished in the 
“ seminal receptacles.” Parthenogenesis being thus ruled out, 
reproduction must have been hermaphrodite. 
Culture C. — Several nephridia were removed, together 
with the larval nematodes Avhich they contained, from a 
freshly killed L. terrestris into a watch-glass with a little 
water. As the nephridia decayed the larvte rapidly matui-ed 
and reproduced. An Fj and an F„ generation were produced, 
and both were cultivated in worm -extract. In this culture, 
males, besides being present in the parental generation, were 
also produced in each of the filial generations. There were 
no cases of undoubted hermaphrodite reproduction, that is, 
in no instance did females which had been isolated while 
larval propagate offspring. Only those females which were 
kept with males reproduced. This is strong evidence for 
bisexuality, but is not decisive, since the females placed 
with the males may not have been fertilised by them, but 
may have produced their own sperm as hermaphrodites, and 
the reason why the isolated females refused to reproduce 
may have been, not the absence of males, but the poorness 
of the food-medium. This objection receives support from 
