122 BULLETIN OF THE BUREAU OF FISHERIES. 
living condition and would fertilize later lots. Such a phenomenon is known to be true 
for the stone crab of our Atlantic coast,* and probably for the edible crab of England.? 
Crabs bearing remnants of a sponge which had been produced during a preceding 
summer were selected during the spring of 1917 and kept under observation until June 
in order to ascertain whether or not they would spawn again. The half a barrel of such 
crabs which was selected on April 18, as already stated, was placed the same day in 
one part of the cove at Lynnhaven Bay, at the time of the initiation of the experiment 
with the other dredged crabs, previously described. During the first week of June 
several sponge-bearing crabs were removed from this part of the cove by the crab 
inspector, Mr. Woodhouse, and sent to Commissioner Parsons. On June 7 the author 
and Mr. Woodhouse removed one sponge-bearing crab from this part of the cove. This 
individual is shown in Plate LI, figure 22, being the one on the lower left. 
On March 22, 19 crabs which bore remnants of a sponge were selected from a lot 
that had been caught with the dredge. These were confined in floats and fed with 
fish during the course of the experiment. On June 4 two spawned and on June 15 
another. On June 22 a fourth spawned. The last was kept under observation, and 
on June 25 the eggs were examined and found to show marked cleavage, proving that 
they had been fertilized and were developing. The individual which spawned on June 
15 was also kept under observation. On June 29 it was found that part of the eggs 
had hatched. By July 2 nearly all the young had hatched and left the mother. The 
crab was killed and dissected. The ovaries were found to contain eggs of about one- 
third full size. Indications were thus given that still another lot of eggs would be laid. 
On April 24 a female crab bearing remnants of a sponge was placed under observa- 
tion. On May 30 this individual spawned. This crab is shown in Plate L, 
figure 19. 
On June 1, in a lot brought in by a trot-line boat, a female crab was found which 
bore remnants of an old sponge and also some eggs, which were recognized by their 
color and appearance to have just been laid. Many full-sized eggs were found in the 
ovaries. This individual had evidently been caught shortly after having begun to 
throw out what was at least the second lot of eggs. The spawning process was thus 
interrupted before completion. 
Further experimentation showed that some of the female crabs lay two batches of 
eggs during the same summer. After about June 20 it was observed that the eggs of 
the majority of the sponge-bearing crabs were beginning to hatch. By July 1 probably 
half the young for the season had beenhatched. (Seetable F.) It was thought possible 
that some of the females which had thrown off a sponge in June would produce another 
lot of eggs that same summer. 
On June 27 a dozen such females were confined in a float. On July 6 one was found 
to have spawned during the preceding 24 hours. Upon examination the eggs were 
found to show faint cleavage lines, indicating that they had been fertilized and were 
beginning to develop. This also shows that cleavage had probably not begun until 
the eggs had been deposited upon the abdomen, otherwise it would have reached a 
@ Binford, R.: The Germ-Cells and the Process of Fertilization in the Crab, Menippe mercenaria. Journal of Morphology, 
vol. 24. June, 1913, p. 161. Philadelphia. 
b Pearson, J.: Cancer (the Edible Crab). Trans., Liverpool Biological Society,, Vol. XXII, 1908, p. 468. Liverpool. 
