176 CRUSTACEANS. 



It was an interesting creature, as if a little dumb companion, having 

 nevertheless had always something to imijart. 



The preceding specimen survived just about two years and eight 

 months. It had borne eight shells, and had undergone seven exuviations. 

 All while under observation. — Plate XL. figs. 2, 3. 



Perpetuation. — The common crab is one of the most fertUe of its 

 tribe. Indeed, were it otherwise, the extinction of the species might be 

 expected with some reason, from the incessant persecution it is exposed to. 



The quantity of roe borne by the female is incredible, and the mul- 

 titude of the offspring far exceeds any probable computation. Did all 

 attain maturity, and propagate in their turn, there would not be sufficient 

 space unoccupied in given bounds for the existence of other animals. 



The common cralj begins to breed at a very early period of its life, 

 during the greater portion of which it probably continues. An ample 

 profusion of roe elevates the apron while the growing parent is yet of 

 very moderate dimensions, which in its origin is very pale, almost white, 

 or faintly yellow.— Plate XLI. fig. 8. 



The season commences with the earlier months of the year, the roe 

 advancing in IMarch and April, also in May or June, as well as more ir- 

 regularly at other times ; that just referred to appeared in October. 



As the roe matures it is converted to fine vivid vermilion. That of 

 a specimen, seven inches broad, was in such quantity as to raise the apron 

 four inches in the middle of March. The ova or capsules were in milUons, 

 still very small, and requirmg some time for attaining maturity. 



In this state it exhibits a sohd mass, which on extrication is 

 found to be composed of numerous clusters of capsules or ova, that ag- 

 gregated individually, that might occupy so many hollow cyUnders. — 

 Plate XLI. fig. 9. A cluster, under the microscope, resembles a bunch of 

 beautiful ripe fruit, not unlike red currants. The clusters are less luxu- 

 riant than the roe of several other species described here, the capsules 

 being more dispersed, nor alike concentrated, as will be seen of the two 

 following species.— Plate XXXVIII. figs. 3, 4, 5. 



Neither is the roe so easily obtained. The female common crab 

 being unmarketable while in roe, the fishermen avoid taking them ; and 



