624 
ME. LUBBOCK ON THE GBNEEATIVE OEGANS, AND 
In excluding the ephippial ova from the category of true eggs, Professor Huxley 
was influenced to a certain extent by the supposition that they are fertile without 
impregnation, and are therefore “ not ova at all in the proper sense, but peculiar buds.” 
According to Steix, however, the reverse is probably the case, and the summer-eggs are 
agamic, while the winter-eggs require to be fertilized*. However this may be, the 
development of the eggs of insects sufficiently proves that eggs composed of several 
ovarian cells, like those which are unicellular, generally are incapable of development 
without impregnation. But no one can deny the name of true eggs to the ova of 
Butterflies, &c. ; and we cannot, therefore, class as “false eggs” those which arise from 
more than one cell. Perhaps it would be better to distinguish the two classes as “ com- 
pound” and “ simple ” or “ unicellular.” The names we may adopt are, however, of less 
importance than the establishment of the fact that throughout the Annulosa there are 
two sorts of eggs, which are of an essentially different structure, and cannot, therefore, 
strictly speaking, be regarded as homologous with one another. 
It is also worthy of notice that among the Articulata a few species possess two 
sorts of eggs. The cases are indeed few ; but as they are also far between {Lacinularia, 
See. among the Eotatoria, Dajjhnia, See. among the Crustacea, and Aphis, Coccus, See. 
among the Insects), we may perhaps see in them the last vestiges of a state of things 
which at a former period may have been general, or at least more common. It is true 
that the existence of two sorts of eggs is generally supposed to be connected with the 
presence of Agamogenesis ; but this mode of generation may perhaps have had the effect 
of retaining a previously existing condition, rather than of originating a new and pecu- 
liar state of things. The cases of the Bee and of some Lepidoptera prove that a double 
method of egg-development is no necessary condition of Agamogenesis. 
Passing on to the other sex, I am not competent to offer any opinion as to the rela- 
tions of the male and female elements to one another, or the homologies existing 
between the product of the male, the semen, on the one hand, and the egg or any part 
of it on the other ; but it is remarkable that, as we And (if I am correct in the view now 
advanced) in the Annulosa eggs of two different sorts, so also there are traces of a similar 
bimorphism of the semen. In Notommata Sieloldii, according to Leydig, the sperma- 
tozoa are of two sorts; Zexker has made the same observation with reference to 
Asellus aquaticus^, in which animal^Ihave also convinced myself of this cmious fact; 
and among Mollusca there is the well-known case of Paludina vivipara. 
Steix J includes also in this category the Common Woodlouse, since while the three 
terminal tubules produce only hair-shaped spermatozoa, the matrix, or receptacle into 
* This is also in accordance with the case oi Da^hnia. In this genus, as in Eotatoria, the “ summer-eggs” 
are agamic, hut it has not yet been conclusively proved that the “winter-eggs” of either require impreg- 
nation. 
t It would appear that (see Yan Be>'edex, Eecherches sur la Eaune littorale de Belgique) the same is 
the case with the allied genus Slabherina. 
t Mulleu’s Archiv, 1842. 
