48 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
the eggs had not yet broken down. The ovary of the larger lobster was similar to 
this, but the process of histolysis had not advanced quite so far. 
The eggs are sometimes absorbed under natural conditions, but why this happens 
is not understood. A very interesting illustration of this fact came to hand on July 
16, 1894, when, on account of its very dark color, my attention was directed to a 
hard-shell female lobster, about 11 inches long. The membranes of the joints of the 
limbs and under surface of the body were of a dull-green color, very unlike the 
appearance which these parts assume in a molting lobster. Examination showed 
that the ovarian eggs were almost completely absorbed and that the blood of the 
animal had a very distinct greenish tinge. The ovary was of a bright lemon-yellow 
tint, the color of the degenerated eggs, decked lightly with green, where an egg had 
not lost its normal appearance. The ovarian lobe had shrunken to less than one half 
its former size. The green pigment which was dissolved in the blood had undoubtedly 
come from the eggs, and had been taken up into the blood faster than it could be 
eliminated from it. I was told by Professor Ryder that the ovarian eggs of the 
sturgeon are sometimes absorbed in a similar way, and the same phenomenon is 
probably met with throughout the animal series. 
In the lobster there are always a few ripe ovarian eggs which fail of extrusion at 
the proper time, which are iuvariably absorbed and give to the mature ovary at the 
next reproductive period a characteristic appearance. (See p. 69 and plate 38, 
fig. 136.) 
One of the females which laid eggs had been kept by herself for several weeks. 
When discovered, on August 24, the ova were in an advanced stage of yolk segmen- 
tation. They were somewhat undersized and of a peculiar light- grayish color. The 
eggs were fertile, although the segmentation was generally abnormal. The lobster, 
which was placed in an aquarium on July 30, was found to have external eggs on the 
11th of August, in a very early stage of development. They had probably been 
extruded during the previous night. These eggs were rapidly attacked by fungi and 
their development was retarded in consequence. Long fungoid filaments grew over 
the surface of the eggs, and diatoms attached themselves in great numbers to the 
egg-capsule. The eggs of lobsters taken under natural conditions are always clean 
and, so far as I have observed, free from vegetable growths of every kind. 
The eggs are fertilized after ejection from the oviducts by the spermatozoa, a 
supply of which is always stored up in the seminal receptacle of the female. There is no 
internal copulation, and no possibility of an internal fertilization in either the ovaries 
or their ducts, as already explained (p. 39). The ova are probably immersed as soon as 
they are extruded, in a liquid cement substance, which is secreted in special glands 
situated in the swimmerets of the female. The “tail” is folded so as to form a closed 
pouch or chamber, as has been observed in the crayfish and other decapods (see 
note 1, p. 47), and the eggs received within it are mixed with the liquid cement and 
sea water. Fixation to the hairs of the swimmerets is finally effected by means of the 
cement, which gradually hardens. How the sperm cells are conveyed from their 
receptacle to the eggs, whether through the medium of the sea water or the glue, or 
whether or not by a motion of their own, is not definitely known. (Page 34, note 1.) 
That the cement is incapable of fixing and holding the eggs until after exposure 
to sea water for some time (perhaps a few hours) was shown in the case of a lobster 
