ORDER BRANCHIOPODA. 
331 
sent strangulations and a swelling, followed by a hinge-joint. 
By means of these organs, or of one of them, they seize either 
the last feet or the end of the tail of their females, in their 
amorous preludes, and retain them in spite of themselves 
in situations appropriate to the manner in which they 
fix themselves. The females carry off the males when they 
do not at first wish to yield to their desires. Intercourse takes 
place as in the preceding Crustacea by prompt and reiterated 
acts. J urine has witnessed three in the space of a quarter of 
an hour. It was believed until his time that the generative 
organs of the males were situated at the upper antennae ; and 
this erroneous opinion appeared to receive some confirmation 
from analogous facts observed in the araneides. On each side 
of the tail of the females is an oval sac, filled with eggs (exter- 
nal ovary, Jurine), adhering by a very slender pedicle to the 
second segment, near its junction with the third, and where 
also the orifice of the deferential canal of the eggs is visible. 
The pellicle forming these sacs is but a continuation of that 
of the internal ovary. The number of the eggs which they 
contain augments with age. At first, brown or obscure, they 
afterwards assume a reddish tint, and become almost trans- 
parent when the little ones are ready to come forth, but with- 
out growing larger. If they are isolated or detached, at least 
at a certain period, the germ will perish. A single fecunda- 
tion (but that is indispensable) may suffice for successive gene- 
rations. The same female can have ten broods of eggs in the 
space of three months. Counting but eight, and supposing 
each of them to consist of forty young, the sum total of births 
would amount to nearly four thousand five hundred millions. 
The duration of the stay of the foetus in the ovary is from two 
to ten days, which depends on the temperature of the seasons, 
and divers other circumstances. The oviferous sacs some- 
times present elongated glandiform bodies, more or less nume- 
rous, which appear to be assemblages of infusory animalcules. 
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