5616 Crustacea. 



autumn; but I have a note of one which was taken entangled in the drift-nets 

 employed in the mackerel fishery, in the first week of April. It keeps for the most 

 part in the deeper water of the channel ; and a remark of Mr. Johns, in his book 

 ' A Week at the Lizard,' is not a contradiction to this, when we consider how far 

 this most southern point of land in all England projects into the ocean : he mentions 

 having seen this crab swimming there at the surface, and that he enticed it to his boat 

 with a bait. All that I have seen, however, have been caught at a good distance from 

 land, in the drift-nets employed for mackerel or pilchards, and in confirmation of the 

 remark already made all have been males. I am informed, however, that a female has 

 been caught, but not under the same circumstances with the males, in comparison 

 with which most of its habits appear to be different. As the nets are hauled into the 

 boats for the most part by night or very early in the morning, these crabs are taken 

 ou board with them, and they will often remain thus wrapped up in the wet twine 

 with little harm for many hours. ■ Transferred to a tank, it immediately shows signs of 

 its agility, by darting round its prison with the activity of a fish, nor does it sink to 

 the bottom until the discovery is made that this great exertion of energy is in vain. 

 It is this power of active motion which has obtained it a local name in the West of 

 Cornwall, where, as crabs in general are termed " cankers," this species is distinguished 

 by the name of " Hying canker." In confinement it is very vigilant, and, like the 

 other swimming crabs (Portuni) shows a readiness to defend itself against threatened 

 danger: its nipper claws are then held aloft, and it seized a hand that was pointed 

 against it, holding it fast with great tenacity. When engaged in swimming the claw- 

 legs are held extended in a straight direction, above the level of the carapace, and 

 the intermediate legs are rowed like oars ; but the hinder legs are lifted above the 

 level of the back, and bent forward over it, their flattened extremities being engaged 

 in very rapid motion. On close examination those hindmost legs are found to be 

 capable of very free and extensive bending forward over the carapace ; but the motion 

 is in two portions chiefly or only : one of those is at the insertion of the coxa, by which 

 the limb is permitted to be thrown up over the carapace towards its outer border, but 

 it is checked in other directions : the other and more active motion is in the two outer 

 joints, which are more especially the propelling oars; their action is in the plane of 

 their compression, and they have a point of support in the two middle phalanges, 

 which move but little, and which, from their more rounded form, contain a larger bulk 

 of muscle. Thus the outer phalanx of this hinder and chief propelling leg is very 

 broad, with a narrow hinge, and admits only of extension to a right line and bending 

 inward: the next or penultimate joint is limited to rotation only, or at least with very 

 little power of extension or bending; and then again the next inward is moved by 

 extension or bending only, and very little by rotation. The coxae of all the legs allow 

 of free and extensive motion. It clearly prefers to feed on living prey : when a living 

 fish was placed in the tank the crab gave chase, and soon seized it with both its claws, 

 killed it, devoured the belly and lower part of the head, but, perhaps being satisfied, 

 rejected the rest. It took a fly that chanced to alight on the water, but lived in peace 

 with a Montagu's sucker for several days, although this fish was also its prey at last. 

 It fed on a dead fish that was thrown to it and lay at the bottom of the tank ; but the 

 death of the individual was probably owing to some dead fish which it did not eat, 

 and which lay for a little while in the water. It appears to remain at the surface only 

 by the energy of its powers of swimming, for no organs of suspension beside the legs 

 have been discovered, and its absolute weight is not less than that of a common 



