[21] OYSTER CULTURE. 3 
which are filled with eggs, the latter in this manner becoming impreg: 
nated. With the lobster and crab the seminal fluid appears to be intro- 
duced directly into the oviducts. As already indicated, the autumnal 
months are, as a rule, the time for the union of the sexes; but, especially 
with the lobster, this time is extended somewhat into the winter. The 
spawning takes place about one month after fecundation. When the 
eggs are ready to issue the female folds the abdominal portion of the 
body against the plastron, thus forming a close cavity into which the ovi- 
ducts open, the orifices being located at the base of the third pair of 
walking appendages. This cavity receives the eggs as they pass from 
the body, and in the course of one day the common lobster will deposit 
in this chamber about 20,000 eggs and the rock-lobster about 100,000. 
During the period of spawning the sides of the abdomen secrete a kind 
of viscous substance, which incloses the eggs, and hardening around 
them, attaches them in irregular groups to the abdominal appendages. 
In this manner the cavity formed by the incurved abdomen soon be- 
comes a nearly solid mass of ova. Incubation now commences, and while 
in this condition the female is said to be ripe. This new stage of repro- 
duction lasts about six months, or until about March to June. During 
this time the female attends closely to the welfare of its eggs. 
By reversing their abdomen as much as the calcareous nature of the 
segments will allow, the eggs are exposed to the light, or by gentle move- 
ment of the false appendages they are subjected to a hygienic bathing; 
now, by refolding the abdomen, the eggs are carefully protected from the 
many dangers which threaten them; and so well is all this managed, 
that among the thousands of eggs of a ripe lobster one can rarely find 
any that are sterile or bad. When the young crustaceans are about to 
escape from the eggs the mother animal assists in releasing them by 
the aid of the spur upon the last joint of the last pair of walking 
legs. With this she detaches the groups of eggs, and at the same time, 
by an oscillatory movement of the false or abdominal appendages, she 
scatters the myriads of newly-born animals on every side. The young 
animal at this time has no resemblance whatever to its parent, and up 
to the date of the recent investigation of M. Coste, to whom we are in- 
debted for the preceding account, these young crustaceans had been 
placed in a special genus under the name of Phyllosomes. These em- 
bryos, with a soft, nearly gelatinous body, are furnished, upon each 
limb and at each joint, with a sort of tuft of vibratile cilia, by the in- 
cessant motions of which they float in the water and are carried about 
in different directions. Upon leaving the maternal protection the young 
animals mount to the surface, and there often form quite extensive 
swarms, which, from the constant movement of the animals and the con- 
stant changes in position of the swarms, sensibly alter the transparency 
of the water. They continue to live in this manner for quite a time— 
thirty or forty days—during which they undergo three moults; finally 
they lose the cilia from their feet, fall to the bottom, and gradually 
