106 BULLETIN OF THE BUREAU OF FISHERIES. 
It will be seen that nearly all the increase in width, which amounted to 1 inch, 
was accomplished almost within the first hour after molting, and that, within 414 
hours, the entire increase was completed. Within 24 hours the shell was too leathery 
to admit of the crab being used as a soft crab. A crab with such a leathery shell is 
usually called a buckram. Within 48 hours the new shell had almost reached the 
usual state of hardness. 
Effect of the moon and tides.—It is a popular superstition that both the moon and the 
tides have a marked effect upon the molting of the crabs. It is supposed that at cer- 
tain stages of the moon more soft crabs, or peelers, or whatnot, may be found than at 
certain other times. In the course of the experiments which were carried on in connection 
with the molting of crabs moltings occurred on the following dates in 1917: May 5; 
June 1, 12, 13, 19, 24, 26, 29, 30; July 2, 4, 9, 11, 12, 17, 21, 27, 31; and August 13, 20, 
and 23. Inno case were there more than two moltings on any of the above dates, and 
usually only one. It would be difficult to establish any relation between the changes of 
the moon and the moltings observed in these cases. No evidence whatever exists for the 
belief that the moon has any effect upon the molting of the crab, and the matter may be 
dismissed as of a class with all folklore superstitions concerned with the supposed rela- 
tion between the moon and mundane affairs, such as the weather, gardening, and the like. 
In many places it is thought that there is a close relation between the rise and fall 
of the tides and the molting periods of crabs. Many persons claim that the young crabs 
molt at every tide or every two tides. This idea is shown at once to be erroneous, since 
at least 48 hours are required for the crab to reach the usual state of hardness after molt- 
ing. The experiments with molting crabs, here described, were carried on where there 
was a tide of at least 4 feet. Some crabs were confined in floats which rose and fell with 
the water, others in wire cages resting on the bottom. No relation whatever was found 
to exist between the movements of the tide and the molting of the crabs. 
The movements of the tides do affect the distribution of the crabs. Immature 
crabs especially tend to come in with the tide. Busters which thus come in with the 
water and soft crabs that have molted after coming in are rather inactive and slowly 
follow out the ebbing tide. For this reason the best time to find such crabs is on a 
“half tide,” as it is falling. This, and other similar facts, have given rise to the notion 
that the movements of the tides actually hasten or delay or in some way regulate the 
molting act. 
AUTOTOMY. 
Closely connected with the process of molting is that known as autotomy, or the 
automatic throwing off of the appendages of the body. This phenomenon is common 
among crustaceans and has been the subject of considerable research. Little work, 
however, has been done in this line in connection with the blue crab. 
If a crab is seized or held by a claw or leg, it often throws off the appendage and 
escapes. The break occurs across one of the segments near the body, there being an 
arrangement to prevent excessive bleeding. The crab is thus often enabled to escape 
with its life at the expense of an appendage. This latter loss is not always as serious 
as might appear as the power to regenerate the lost appendage is possessed by the crab, 
at least until the molting stages are completed. If the loss occurs shortly after a 
molting, the regeneration will be made at the next molting. If it occurs only a few days 
before a molting, the renewal takes place at the second subsequent molting. 
