154 MAIUNE FAUNA OF ST. ANDREWS. 



circumstances the body is coated with mud, which fills up the 

 in-egularities of its conformation, and loads the abdominal 

 feet and hairs ; yet the crab is vigorous and healthy, and out- 

 lives sanitary apprehensions. 



Under almost every stone within reach of the tide young 

 specimens occur. At low water the full-grown crabs seek the 

 hiding-places just mentioned, or shade themselves under the 

 blades of the seaweeds in the rock-pools. Occasionally one is 

 found adhering to the soft body of a moulting brother and, 

 cannibal-like, devouring the branchiffi, new carapace, and other 

 .soft organs with savage pertinacity, while the old shell has 

 not quite fallen from its victim. Moiilting shore-crabs are 

 generally found alone, as if aware of their helplessness, 

 and dreading, with some degree of justice, the voracity of 

 enemies and even unscrupulous relations. Very slight injury 

 kills them in this condition ; and of course, for a time, they are 

 incapable of defending themselves from even weak assailants. 



The shore-crab is found in pools at the East Eocks where no 

 other marine articulate of the same class occurs, and the water 

 cannot but be brackish, since the pools are not filled by ordinary 

 tides, and fresh streams from the crags flow in the neighbour- 

 hood. In these resorts the colour of the crab is not so pretty, 

 being of a muddy green with pale limbs ; and the specimens 

 in the highest pools are generally small. It is not surprising, 

 however, to find them in sucli places, after watching their 

 activity in the innumerable brackish lakes of the Outer 

 Hebrides, and their evident comfort in perambulating the 

 muddy flats even where streams of fresh water abound. 



On land, Oarcinus mcenas 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 chelaj ; 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 liave recently repaired 

 wounds of the carapace (Plate IX. fig. 12) ; others have lost 



