LIFE HISTORY OF THE BLUE CRAB. 117 
Within a few weeks the pink jelly will be found to have disappeared, leaving the 
sacs flat again, but with a white ridge along their lower side (Pl. XLVIII, fig. 6). The 
spermatozoa will be found stored in this ridge. They are carried from the male by 
the jelly in bundles of an oval shape slightly larger than the eggs of the female. Such 
bundles are called spermatophores, and one is shown in Plate XLVIII, figure 8. The 
spermatophores disintegrate as the jelly disappears from the sperm sacs and the sperma- 
tozoa are found to lie in a mass in the white ridge at the bottom of the sperm sacs. 
Drawings of the spermatozoa which have been mounted for microscopic study are 
shown in Plate XLVIII, figure 9. 
Development of the ovartes.—The ovaries enlarge until they are about one-half 
inch in width (Pl. XLVIII, fig.13),at the same time becoming a bright orange-red color. 
The color is due to yolk granules in the eggs, as described earlier. If examined micro- 
scopically, some of the eggs will be found to have reached the size at which they are 
when laid upon the abdomen (PI. XLVIII, fig. 1). Smaller eggs, which will be laid 
in subsequent batches, will also be found. 
The enlarging of the ovaries is not dependent, however, upon copulation. It has 
been found that they enlarge and the eggs likewise increase in size, even if copulation 
has not occurred. On June 19 a female crab with the triangularly shaped abdomen 
was placed in a float with no male present. On June 25 it molted, the abdomen chang- 
ing to the rounded form. On July 21 this crab was killed and its ovaries examined. 
They were found to have attained, during this period of only 26 days, to about one- 
half the full width. The eggs were about one-half the mature size. The color was 
orange. The sperm sacs were thin and flat, as already described for the crab which 
was removed from the male immediately before copulation. There was no white 
ridge found along the lower side, such as is present in a crab which has copulated. It 
is possible that such a crab would lay the eggs when they had attained the full size, 
but they would, of course, be infertile, and therefore would not hatch. 
It is thought by many crabbers that the abdomen of the female will not change to 
the broad form unless the male is carrying the female at the time of the last molting. 
This is shown to be an erroneous idea, both by the evidence of the experiment just 
cited and by the fact that at least four other female crabs were allowed to undergo 
the last molting while under observation, no male being present, and in each case the 
normal, broad abdomen appeared. 
Probably very few female crabs, however, pass the last molting stage in nature 
without mating. Observations made at various times on at least 300 adult females 
revealed none which had failed to undergo copulation. 
Fertilization —The eggs are, in all probability, fertilized as they pass through the 
sperm sacs on the way from the ovaries to the exterior at the time of spawning. The 
spermatozoa are found in the sperm sacs, as before stated. The author was able to 
find no evidence that would lead to the belief that spermatozoa pass up into the ovaries 
and meet the eggs there. Eggs taken in May from the hollow in the middle of the 
fully developed ovary gave no appearance of having been fertilized and did not develop 
when kept in sea water. On the contrary, they always become swollen within the 
course of 10 or 15 minutes (Pl. XLVIII, fig. 12), apparently from haying absorbed water. 
Eggs taken from the sponge of the female were found to be covered by a tough trans- 
