244 HALF AN HOUK WITH CRUSTACEA. 



all over with spines, like that species ; the shell being 

 of a pale red, and the spines of a darker hue. 



There is a group of crabs which go by the 

 name of " Swimming-crabs," and have their claws 

 modified for the purpose of swimming, as well as 

 crawling along the sea-bottom. One of the com- 

 monest of these is the " Velvet Swimming crab," or 

 " Velvet Fiddler," as it is also called (Portunus puber). 

 There is no difficulty in separating the crawling from 

 the swimming crabs. The former always have the 

 hind legs round, whilst those of the latter are 

 flattened and oar-like. The species we have just 

 mentioned has a broad shell, or carapace, toothed in 

 front, with the front claws covered with little 

 tubercles. It is bright and showily coloured, 

 although the colours soon fade after death. Off the 

 coasts of Devon and Cornwall this is a very common 

 species. Its size ranges from two to three inches. 

 Another species haunts the same habitat, but extends 

 further along the western coasts. This is the 

 " Cleanser Swimming-crab," whose shell is of a pale 

 red colour. There are several other species of 

 Portunus to be met with off the English coasts. 



The " Hermit-crab " (Pagurus Bernhartfus), which 

 may be found in every heap of trawler's rubbish, 

 is one of the most singular creatures known. It 

 takes its name from its habit of living in the empty 

 shells of univalve molluscs, that of the common whelk 

 being a favourite. The great peculiarity about it is 

 that its belly, or abdomen, is always soft, and not 



