NATURAL HISTORY OF AMERICAN LOBSTER. 
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immediately in the cytoplasm, and henceforth the growth of the egg is determined by 
additions to the store of yolk, the materials for the manufacture of which are supplied 
by the blood. At an early stage the eggs probably multiply by division, and where 
they do not immediately break away from the parent epithelium they become elongated 
by mutual pressure, so that their long axes are parallel to each other and perpendicular 
to the basement membrane. Irruptions of ova, however, always occur at certain points, 
so that the young eggs appear in bunches along the crests of the original folds. 
The nuclei of those cells destined to form a part of the follicle are easily distinguished 
by their smaller size, rod-like form, and by the relation to the young eggs which they 
promptly assume. The nucleus or germinal vesicle grows apace and continues to 
expand until, at the close of the first year after a given ovulation, it attains a diameter 
of one-eleventh millimeter. Rarely two or more nucleoli are developed in the young 
eggs; there is usually but one nucleolus and this of large size. 
When sections of the ovary are examined, after treatment with the usual killing, 
fixing, and staining fluids, we find the nucleoli of all the eggs lying against the nuclear 
wall in the same relative positions; that is, at the “bottom” of the nuclei or on the side 
which was lowest at the time of fixation. The nucleolus is apparently released from 
its suspension in the nuclear reticulum by the action of the fixative employed, and 
responding promptly to the influence of gravity, drops like a shot in a bag. The ulti- 
mate position of the nucleolus is thus solely determined by the direction of gravity, 
and in reference to the egg itself by the position of the tissue at the time of fixation. 
The growth of the first generation of eggs is exceedingly slow, occupying from four 
to five or more years, during which the ova must derive their nourishment indirectly 
from the blood. Swarms of new cells which continue to arise along the axial folds 
tend to drive the largest and oldest eggs toward the outer walls, a condition which is 
maintained until these ova approach maturity. When the limit of growth is reached 
the eggs are dehisced from their capsules, fill the lumen of the ovarian tube, and crowd 
the germinal folds and younger eggs of the next generation farther and farther toward 
the periphery. 
We have already referred to the variable color of the organs during this period of 
their growth. Bright yellow, flesh and salmon color, light olive green, with many inter- 
mediate tints, are commonly noticed, while after the first eggs are produced, uniformity 
in the color of the organs prevails. With rare exceptions, after the first egg laying the 
ovary in due time assumes a characteristic light pea-green color and becomes progres- 
sively darker with age until maturity is reached. 
CYCLICAL CHANGES IN OVARY AFTER THE FIRST SEXUAL PERIOD. 
We have finally to consider the changes which the ovary normally undergoes during 
each successive reproductive period. After the eggs are laid the collapsed organs assume 
a grayish-white tint and appear flecked with green spots — the residual ova which fail 
of emission and stick fast in the lobes and ducts. In the course of 36 hours or less the 
ovaries are again solid masses with central germogenal folds, the larger eggs lying nearer 
