Crustacea of St. Andrews. 339 



On land, Carcinus mamas is, perhaps, the most active British 

 crab, especially in regard to offence, defence, and escape. It 

 scrambles over the rugged rocks with astonishing speed, while 

 defending itself with its uplifted cheke ; and so fierce is it in 

 attack, that having once seized an object with the latter the 

 spasmodic effort is sometimes so great that the limb separates 

 from the trunk at the base. The males frequently engage in 

 combat ; and a fatal issue would more frequently ensue, were it 

 not for the provision whereby hemorrhage is speedily arrested 

 and the lost portion repaired or reproduced. Few specimens, 

 indeed, are quite free from injury. Some have recently repaired 

 wounds of the carapace, others have lost an eye, an antenna, 

 or one or more limbs. They surpass most marine animals in 

 their powers of enduring life at a distance from sea-water, and 

 may easily be kept for several weeks in a botanic vasculum. 



The shore-crab is strictly carnivorous and, as already men- 

 tioned, even relishes its fellows. It is a curious feature in 

 its history that it suffers serious annoyance and injury from 

 the young of the common mussel, which plant themselves 

 in its orbits, in the sockets of the internal antennse, in the 

 branchial chambers, and under the tail — in the former case 

 often destroying both eyes. It feeds with avidity on the 

 mussel in its adult state ; so that here is an instance of a help- 

 less young form avenging the destruction of the mature. The 

 shore-crab, again, is devoured by many fishes : thus in the 

 stomach of a Coitus bubalis I have found five or six specimens, 

 two entire and upwards of two inches across the carapace. 

 The Cottus, however, unfortunately came in the way of a large 

 frogfish, which found a place for it in its capacious stomach, 

 though nine full-grown flounders were already present. In 

 many parts of Britain and the continent the shore-crab is used 

 as food by man (and this is a safe-enough practice so long as 

 it is well boiled, internal parasites being abundant) ; but at 

 St. Andrews it is only employed occasionally for bait. 



Myriads of the young of this species in the zoea-stage 

 occur at the surface of the bay in autumn, and may easily 

 be kept alive, so as to show the subsequent stages of develop- 

 ment. 



Besides those already mentioned, many of the other forms 

 are very common, such as Stenorhynclius rostratus, Inachus. 

 Hi/as, Portumnus variegatus, the Portuni, Pinnotheres, Ebalia, 

 and Nephi-ops in deep water, Porcellana, the Paguri, Galathea. 

 and Crangon between tide-marks, and in both regions Hippo- 

 lyte, Pandalusj and Palaimon. In deep water swarms of Hi/as 

 coarctatus for the most part take the place of H. araneus. As 

 a littoral form Palcemon squilla is local, but in company with 



