LIFE HISTORY OF THE BLUE CRAB. 119 
SPAWNING EXPERIMENTS WITH CRABS TAKEN DURING THE WINTER. 
The fact that the female crabs mate during one summer and do not spawn until the 
next, as stated in the preceding paragraph, is proved by the following examinations and 
experiments: During the winter of 1916-17, 238 adult female crabs taken from the 
catches made by various dredge boats were examined. In each case specific records 
were kept of the condition of the ovaries, sperm sacs, eggs, etc. In 204 of these, the 
ovaries were found to be large and full, as shown in Plate XLVIII, figure 13, and Plate 
L, figure 18. In 30 cases the ovaries were small, but microscopic examination re- 
vealed the presence of small eggs within them. Four crabs taken early in the season 
had recently copulated, as was shown by the presence in the sperm sacs of the pink, 
jellylike fluid (Pl. L, fig. 17). The sperm sacs of the other 234 crabs had the small 
white ridge along the lower side (Pl. XLVIII, fig. 6). Spermatozoa were found 
within the mass which made up this ridge. Plate XLVIII, figure 9B, shows some of 
such spermatozoa after having been mounted for study. Every appearance was given 
that these crabs had mated during the preceding summer and would survive the winter 
and spawn the following summer. 
To test this matter more fully, the following experiments were performed: Twenty- 
eight adult female crabs which had been taken on March 28 with the dredge were placed 
in a crate made of chicken wire fencing and measuring 2 by 2 by 4 feet. This crate was 
placed in water of such a depth that it was entirely covered at low tide. The crabs were 
fed nearly every day with pieces of fresh fish. On June 28, 8 crabs were living, one of 
which bore a sponge of normal size. On March 22, 19 crabs which had been taken with 
a dredge were confined in floats in the water of the Bay. These crabs were fed with fish. 
On June 15 one spawned, and on June 22 another spawned. The latter was kept under 
observation, and upon microscopic examination on June 25 the eggs showed marked 
cleavage, proving that they had been fertilized and were developing. 
Through the courtesy of John S. Parsons, late commissioner of fisheries of Virginia, 
the author was enabled to utilize a small cove at Lynnhaven Bay, Va., in which to keep 
crabs under observation. Wire netting was placed across the mouth of the cove in such a 
way that the crabs were prevented fromescaping, while allowing direct connection between 
the water of the cove and that of the Bay. The cove was divided by a close, wooden 
partition, so that two independent experiments could be maintained simultaneously. 
On April 18 the author accompanied a dredge boat which secured 2% barrels of 
crabs in Lynnhaven Roads, east of Norfolk, Va. On the same day these were put in one 
part of the cove by the author and Messrs. Owens and Woodhouse, crab inspectors of the 
the State of Virginia. During the first week in June several dozen crabs bearing sponges 
were removed from the cove by Mr. Woodhouse and sent to Commissioner Parsons. 
On June 7 the author and Mr. Woodhouse removed from the Cove six sponge-bearing 
crabs. ‘Two of these are shown in Plate LI, figure 22, being the two at the right of the 
picture. Quite a number of others were seen in the water of the cove. Apparently they 
spawned there about as freely as in their natural habitat. 
From the evidence of these examinations and experiments it is plain that the con- 
necting link is perfect between the crabs that mate one summer and those that spawn 
the summer following. The great bulk of the crabs of Chesapeake Bay, after mating in 
Maryland waters where they matured, move to the lower part of the Bay, retain their eggs 
during the winter, and spawn the following June and July. 
