Crustacea. 839 



from the coast of Norway to the Billingsgate market, in well -boxes, 

 which are of wood, very strongly constructed, and with holes in all 

 the sides, to admit of continual change of water, as the boxes are 

 drawn through the sea, attached to the vessel." — p. 63. 



Common shore crab (Carcinus Mamas). " Its food consists prin- 

 cipally of the fry of fish, of shrimps, and other Crustacea, but it will 

 feed also upon dead fish, and almost any other animal substance. 

 Indeed, the most common method of taking these crabs at Poole, 

 where numbers are caught by the fishermen's children, is by tying a 

 mass of the intestines of either a fowl, or of any fish to a line, and 

 hanging it over the quay; the crabs seize upon this bait, and are 

 drawn up in considerable numbers. Mr. Hailstone states, that they 

 attack mussels, and that he once saw one carrying about on its hand 

 a mussel which had closed its shell upon it. They run with con- 

 siderable rapidity, and with an awkward sidelong gait ; and they lurk 

 in pools of water left by the tide, partially concealed in the sand, but 

 w T ith the anterior part of the carapace, including the eyes, exposed, 

 so as to watch for the approach of their small living prey, on which 

 they spring with great activity. They are, however, very timid and 

 wary, and will not move if they discover that they are watched. 

 They simulate death, if disturbed, as completely as do many Coleop- 

 terous insects. The process of exuviation takes place at various 

 parts of the year, from spring to autumn. I have found the female 

 carrying spawn as early as April, and as late as September. The eggs 

 continue to increase in size in this and in the rest of the Portunida?, 

 until the abdomen is forced backwards to an obtuse angle with the 

 body. Like most of the Brachyura, this species buries its ova in the 

 sand ; and ' when they are disengaged,' says Mr. Couch, ' the crab 

 stands high on the points of its legs, and employs a couple of them, 

 one on each side, in working the loose tendrils to which the ova are 

 attached.' For the following interesting account of the development 

 of this species, I am indebted to the kindness of the same indefatiga- 

 ble observer. ' The ova come to life in about forty-eight hours or less. 

 The following are my notes made at the time of observation, on one that 

 bred in captivity. It seems clear that each ovum has two investing 

 coats, one proper to it, the other in which it is enclosed as attached 

 to the parent. The latter has a thread, a portion of which is seen 

 attached to the ovum after it has been thrown off. The ovum bursts 

 on the sides opposite to this thread, and the creature first protrudes 

 the abdominal portion, or that which is behind the carapace, and 



