370 Experimental Zoology 
In some species the females have neither the “disposition”’ to 
unite with male individuals nor the apparatus for storing the 
sperm. Males occur in some of these cases, but they also often 
lack the sexual instinct, and their spermatozoa are condemned 
to perish. 
Another point of great interest has been made out by Maupas, 
viz., the imperfection or insufficiency of the hermaphroditism. 
More eggs are produced than there are spermatozoa present to 
fertilize them. Those that are first set free from the ovary 
become fertilized, the rest become rapidly disorganized. The 
number of fertilized eggs produced by a well-nourished individ- 
cual is only about 200 to 250.‘ This condition is far from being 
an advantage to the species, for if separate sexes existed, at least 
800 eggs might be fertilized. If only half of these eggs produced 
females, still the number would be 400, which is larger than the 
number of individuals produced by the hermaphroditic species. 
In the second generation there would be 160,000 individuals 
from the unisexual females, but only 60,c00 hermaphroditic 
females. Thus there is no reason to suppose that this herma- 
phroditic condition is the result of an adaptation of the species. 
Instead of an advantage it is a process injurious to the species, 
but suffices, nevertheless, to keep it in existence. 
Males appear in these hermaphroditic species, but in relatively 
small numbers. Maupas has given the proportions observed 
in the following table: — 
Diplogaster robustus . 2 6 . ©.13males } 
Rhabditis guignardi . ‘ . . 0.15 males 
Rhabditis dulichura. F ‘ . 0.7 males 
Rhabditis caussaneli . : : . 1.4 males 
Rhabditis elyaus 2 F : . 1.5 males 
Rhabditis coronata 3 2 . . 5.0 males Wao tewtalks 
Rhabditis perrieri ‘ : . . 7.0 males 
Rhabditis marionii ‘ : : . 7.6 males 
Rhabditis duthiersi F P , . 20.0 males 
Rhabditis viguieri - ‘ . - 45.0 males 
‘In one species only, Rhabditis guignardi, there are more, namely, from 520 
to 530. 
