168 CRUSTACEANS. 



peculiarities are involved, especially the change of the shell, whereby 

 they are entirely regulated. 



The common crab is both the largest bodied and the strongest of its 

 genus pertaining to Scotland. I have heard some vague accounts of an- 

 other, described as exceeding its size, but, considering the prevalent ex- 

 aggeration of facts not to be immediately verified, and especially relative 

 to marine products, I do not feel much disposed to rely on such assertions. 

 Nevertheless the limbs of the Cancer horridus, as we shall see, certainly 

 expand farther. 



This species, the Cancer pagurus, is more of uninterrupted oval form 

 in proportion than any of the others ; the claws stronger, perhaps, and 

 the limbs shorter ; the apron, also, is narrower than that of the rest of 

 its family here described, the Cancer mcenas, Cancer or Port 'tmtis liridus, 

 and the Cancer or Port units pusillus. Nine prominent flutings, com- 

 mencing with each eye in front, border the shell. The eyes are sus- 

 tained on peduncles considerably apart, rather low and small, and be- 

 tween them a pair of larger and a pair of smaller antenna?. Three of 

 the flutings are on the margin of the shell, opposite to these organs. 

 The surface of the shell, finely granulated, is of a reddish brown colour, 

 and the tips of both claws jet black, a strong and decisive feature. 

 Plate XXXVIII. fig. 1, upper surface ; fig. 2, under surface. 



When roused by hunger, the Cancer paaiirus is fierce and rapacious. 

 Regardless of superiority in size or in strength, it springs on whatever 

 it desires to render a prey ; and feeds greedily on all animal substances, 

 whether living or dead, fresh or putrid. Everything is seized and de- 

 voured, and the stomach being very capacious, considerable quantities 

 are consumed at a time. Nothing is rejected, and the repast is repeated 

 frequently. In common with its tribe, however, it is patient of absti- 

 nence, ceasing to feed before exuviation, and sometimes after it. I 

 could not ascertain that a small specimen, received through the favour 

 of Dr Duguid, a learned naturalist, from Kirkwall, fed for a complete 

 month or longer. In the course of another month it devoured a 

 shrimp. 



But this species, apparently strong, is alike delicate as others ; 



