REPORT OF COMMISSIONERS OF INLAND FISHERIES 71 



or mottled with IjIuc. This pecuHar appearance is considered a sure 

 sign, not only that the crab will moult soon, but that, having moulted, 

 the tail will change in shape, become larger and more nearly round. 

 This results in the so-called "half-moon" shape. Female crabs 

 with the "half-moon aprons" have never been known, it is said, to 

 moult or even to show signs of moulting, although they have been 

 kept for a long time in cars and fed generously. Furthermore, 

 specimens of this sort are often caught with barnacles and forests of 

 algae on their backs, which indicates that a long time has elapsed 

 since they last shed their shells. 



The male crabs have no characteristic "aprons" to indicate the 

 close of their moulting period, but as male crabs averaging about the 

 same size have been observed with very hard shells and an abundance 

 of barnacles and seaweed, it would seem as though the males also had 

 a moulting limit. Again, crabs in any particular locality almost 

 never exceed a certain size; and since there is normally a growth of 

 about one-sixth at each moult, this fact is regarded as further evi- 

 dence that the limit is fixed. 



The crabs which are actually preparing to moult become very 

 sluggish and will not eat; and yet, if they are kept in confinement 

 without food even for a comparatively short time before this, the 

 process is much delayed, and afterwards the crabs are light and 

 watery. 



Individuals which have moulted require a large amount of food, 

 but ordinarily the crabs may live a long time without it. A story is 

 told, on apparently reliable authority, of a crab which was kept in a 

 car for three months without any food except what was carried into 

 the car by the tide. When finally, out of pity, it was released, it 

 was still lively, and showed no permanent effects of starvation. The 

 writer has kept a specimen over a month without food. 



Migratory Movements. — At certain times of the year crabs move 

 off shore regularly before winter sets in, but sometimes also during 

 the summer months. At such times they seem to go suddenly, and 

 disappear from all parts of the Bay at the same time. Fishermen 



