606 
ME. LUBBOCK ON THE GENEEATIVE OEGANS, AND 
rally, after the egg was crushed, could no longer be perceived; once, however, I 
succeeded in isolating it from the yelk, when it took the form of several clear masses 
apparently of a glairy substance, without any membrane, though with a clearly defined 
border. In this case the Purkinjean vesicle contained a number of small cellular 
bodies, about -gif o o^^ of i^oh in diameter, and exceedingly like the embryo-cells of 
Coccus*, having the same greenish tinge and somewhat angular outline. The yelk- 
masses, which were at first transparent, turned an opake yellow under the action of 
water; but the process was much slower in some than in others. Acetic acid only 
slightly darkened the eggs, and did not bring any vitelligenous cells into view. It com- 
pletely udped out the macula. Under ammonia the young follicles became very faint, 
and the Purkinjean vesicle disappeared. 
The largest eggs in which I found Purkinjean vesicles were from 2oo6d hs to -j^f^ths 
of an inch in diameter, the vesicle being about one-third of that size. 
The mature eggs from the cavity of the ovary were about a^ths in diameter, and 
nearly spherical in shape. They contained the usual yelk-masses, of which the larger 
ones were g-jpQoths of an inch in diameter, and under pressure split at the sides like 
those of lulus. They contained no Purkinjean vesicle. 
I was for some time much puzzled by finding among the ordinary eggs certain spindle- 
shaped bodies, some of which were very narrow, while others were so broad as scarcely 
to differ from the spherical eggs, except by having one side flattened. They were 
surrounded by a layer of epithelial cells, contained ordinary yelk, with generally a 
Purkinjean vesicle, and in fact possessed all the characteristics of true eggs. For some 
time I believed that, besides the spherical eggs, other more or less spindle-shaped ones 
were produced in the ovary of lAthohius, so that, as in Baphnia, the same ovary gave rise 
to two sorts of reproductive bodies. At length, however, it occurred to me to cut off 
part of a young egg ; and I then at once found that the larger portion of the wounded 
egg was one of my spindle-shaped bodies, which therefore were nothing more nor less 
than the ova which had been accidentally cut through in the dissection of the ovary. 
If, however, the eggs are too large, they simply burst when cut, and the contents escape. 
The most suitable ones are those which contain granules and have not yet developed 
any large oil-globules. This observation would be scarcely worth mentioning, were it 
not that the cut surface of the yelk presents an outline which is as well defined as 
the other parts, and shows no trace of the wound. It is of course evident that this part 
cannot be surrounded by any membrane, and the similar appearance presented by the 
rest of the yelk is therefore deceptive. So definite or clear, however, is the outline, that 
it is difficult not to believe in the presence of a vitelline membrane, and it seems pro- 
bable that the membrane described as surrounding the egg-germs of some other animals 
may have its origin in a similar deception. 
The numbers of the two sexes seem to be nearly the same : thus out of thirteen speci- 
* Philosopkical Transactions, loc. cit. p. 364!. 
