292 
bulletin of the bureau of fisheries. 
the periphery, where the epithelium has become decidedly glandular in appearance. 
(Fig. 4, pi. xlv.) These gland-like organs apparently contribute to the growth of 
peripheral eggs for a short period and subsequently disappear. Amoeboid cells pass 
from them into the eggs, where their nuclei degenerate, giving rise to swarms of fine 
chromatin-like granules, which persist for a considerable time. In 5 weeks from the 
date of oviposition the gland-like bodies are reduced to shrivelled remnants, of which 
later no vestige can be recognized. 
While the massive yolk of the eggs is mainly derived from materials drawn from the 
blood and laid down at first in the cytoplasmic reticulum, the migratory cells just 
described contribute in a minor degree toward the supply, and the glandular follicles 
possibly manufacture yolk directly, although the evidence which seems to support this 
idea may be wholly deceptive, owing to the presence of degenerative elements. 
In the course of 5 or 6 weeks the ovary, flecked with degenerating eggs which failed 
of passage and now of a bright orange color, begins to assume a light-green tint. Exami- 
nation of the larger ova shows that the pigment, a green lipochromogen, is first formed 
in the yolk spheres immediately around the nucleus and thence spreads centrifugally 
until it involves the entire yolk mass. In a year’s time, or at the beginning of the 
summer following ovulation, the peripheral eggs, while but little larger, are more uni- 
form in size and color, and the whole organ presents a characteristic pea-green tint. A 
second period of active growth ensues, followed by a second interval of quiescence during 
the winter. At the beginning of the third summer after the last ovulation these eggs 
enter upon their third and last period of active growth and are soon ready for extrusion. 
(Fig. 5, pi. xlv.) 
Owing partly to the presence of the egg membrane or chorion, absorption of the 
residual eggs at each period of laying is exceedingly slow. After the lapse of 2 years 
traces of them can be detected, and the presence of these orange flecks in the ovary of 
any lobster tells us conclusively and at a glance that it has already spawned once at 
least. 
The ripe eggs, as spawning time approaches, lie free in the lumen of the ovary, 
which they distend to an unusual size, its elastic walls becoming very thin in consequence. 
Maturation may be completed in the ovary itself, but fertilization is possible only after 
the eggs have been expelled from the body. The massive yolk is inclosed in a flexible 
and transparent shell or chorion, secreted, as we have seen, by the egg follicle or sac, 
and by the time the ovum has reached the ducts its nucleus (female pronucleusl has 
migrated to the surface. The ripe egg possesses a single membrane only. 
DISTURBANCES IN CYCLICAL CHANGES OF THE OVARY. 
It is convenient to notice here what the fishmonger in England sometimes calls 
"‘black lobsters.” During the summer months the English lobster dealer is said to 
examine his stock daily and to cull for immediate sale such animals as show a tendency 
to blacken. It seems that whenever females with ripe ovaries happen to be caught 
and are either sent to market or kept in floating cars, the normal reflexes which attend 
