LIFE HISTORY OF THE BLUE CRAB. I2I 
clipped off with the scissors and examined with the dissecting misroscope. It was 
found that very little or no bleeding resulted and that the crab very seldom, if ever, 
died as a result of the removal of the tips of the hairs in this manner. Such individuals 
could, therefore, be kept under observation to await subsequent spawnings. 
The presence of such remnants of a sponge upon the swimmerets of a female crab 
is conclusive proof that she has at one time laid a batch of eggs, presumably during 
the summer immediately preceding. The absence of any such remnants is not proof 
that the individual in question has never spawned, since all the hairs may have become 
entirely cleared of any portions of the sponge. It was seldom found that many hairs 
bore remnants; in many cases they would be found upon only one or two located at 
the tips of the anterior swimmerets. 
During the winter and spring, in almost any barrel of crabs which was examined, 
it was possible to find without difficulty females bearing such remnants of a sponge. 
On April 18 the author accompanied a dredge boat which was working in Lynnhaven 
Roads, Va. Three barrels of crabs were dredged in about five hours’ time. During 
this time, with the aid of a dissecting microscope, one-half barrel of crabs which bore 
remnants of sponges was selected from those dredged. This means that at least 1674 
per cent of those dredged up on this occasion had spawned during the preceding summer. 
As not nearly all those obtained were examined, owing to lack of time, the actual pro- 
portion bearing remnants was no doubt greater than this. Most of those which bore 
remnants appeared to be vigorous and capable of living the remaining weeks until 
June. 
On May 15 seven females were removed from a barrel of crabs that had been caught 
by the trot-line. All were living. Upon examination it was found that three had 
spawned during the preceding summer. Crabs bearing remnants of an old sponge usu- 
ally have a peculiar rusty-brown color which is not possessed by the other females. 
This is probably due to the fact that the former are older and have usually survived two 
winters. In searching for remnant-bearing crabs this color characteristic proved to be 
a useful guide. The proportion of three to four, apparently, as just shown, would not 
hold for the entire barrel, since the seven crabs were not selected at random, but with 
reference to the brown color. 
As late as June 1 it was possible to find individuals bearing remnants of the sponge 
of a previous season. hus it is plain that the crabs which have spawned during one 
summer may survive throughout the winter until the following spawning season. 
Crabs which carried remnants of a sponge were dissected during the winter and 
spring of 1916-17. This examination led to the belief that such crabs were capable of 
spawning the ensuing summer. The ovaries were large and full; in fact, they appeared 
in every way similar to those of the individuals which had mated the previous summer 
and had not yet laid any eggs. (Compare Pl. XLVIII, fig. 13, and Pl. L, fig. 18.) The 
sperm sacs were found to contain the white ridge or mass (PI. XLVI, fig. 6), in which 
spermatozoa (Pl. XLVIII, fig. 9B), were found, as in the case of the other crabs. Appar- 
ently enough spermatozoa were provided by the male at the time of the one copulation 
which the female underwent to fertilize successive batches of eggs. What was not uti- 
lized at the passage of the first lot of eggs through the sperm sacs remained there in a 
