98 ME. LUBBOCK’S ACCOUNT OF THE TWO j\IETHODS OF EEPEODUCTION 
female animals, entii’ely different sexless indi\iduals), in liis latest and rery interesting 
essay, “ Wahre Parthenogenesis bei Schmetterlingen nnd Bienen,” admits that the self- 
fertile indiAdduals in these insects are true females. 
This is also not the less evident in Daphniw, for in them not only may the same 
specimen produce first agamic eggs, then ephippial, then again agamic, and then again 
ephippial eggs, so that it would have to be considered fu’st sexless, then female, then 
sexless and then female again, but actually, and that usually, the embrv’onic forms of 
both eggs are present at the same time. Plate VI. fig. 3, for instance, represents a specimen 
with an ephippial egg, beginning at the posterior end of the ovaiy, and some agamic 
eggs in front : and as this is no solitaiy exception, but in far more than half the specimens 
I have watched, this contemporaneous development of the early stages of both eggs has 
occurred ; and as in most cases the agamic eggs are developed, and the others disappear, 
there can be no doubt that the self-fertile specimens are females. 
Throughout this paper I have applied the name of eggs to the ordinary reproductive 
bodies of the Baphnice, although aware that it is customaiy to call all egg-like bodies which 
are fertile without immediate impregnation “ mternal buds ” or “ gemmae,” and to con- 
sider them as essentially different from true eggs. Dr. Caepenter* and Dr. BuRXETTf 
have adopted this theory, and M. de Quateefages also J says, “ Seulement chez les demieres 
[mnged female Aphides, in opposition to the so-called sexless specimens] on ti’ouve de 
^'eritables oeufs, pourvus de toutes leurs parties caracteristiques ; chez les premieres de 
petites masses granuleuses, ou Ton ne distingue jamais ni Vtellus, ni vesicule germinative, 
ni tache de Wagnee.” 
In this statement he probably relies on the descriptions of J. Y. Carls and Dr. Bue- 
XETT, but Leydig has already shown that there is good reason for supposmg them to be 
ill error ; at any rate it is by no means apphcable to the Baphnice. In these we find in 
the ovary a number of ovarian masses containing small cells. One of these latter swells, 
dark granules collect around it, and it becomes a germinal vesicle. This is the foimda. 
tioii of an ephippial egg (see Plate VI. fig. 2). Just in ffont, another cell swells a 
little, becomes surrounded in a similar manner by dark granules, and also by oil-globules, 
and this process continuing, forms the ordinary egg. I say egg : for how can we deny 
this term to a round body developed in the ovary of a female, and round a germinal 
vesicle '? 
Truly has M. de Quateefages observed §, “ Ainsi Ton passe de la simple croissance 
d'un mammifere, au bourgeonnement le mieux caracterise par des nuances insensibles : 
et tout nous ramene a cette importante conclusion, que le boiu’geonnement, et pai‘ con- 
sequent la reproduction agame, ne sont au fond qu’un phenomene d’accroissement.” But 
why stop the series here \ Dr. Burnett says, indeed ||, that “ the structm-e and conditions 
of all true ova are the same, and there is no passage between them and buds : ” but this 
* See Dr. Caepenteb ‘ On tlie Microscope and its Eevelations,’ p. 279. 
t Loc. cit. 
§ Loc. cit. p. 129. 
t Loc. cit. 111. 
II Loc. cit. p. 88. 
