292 transactions liverpool biological society. 



Introduction. 



Cancer is a genus which has a world-wide distribution. 

 Only one species, however, is found in Europe, viz., Cancer 

 pagurus, the subject of the present memoir.* This species 

 is found on almost every part of the coasts of Europe from 

 Norway to Greece, and it is particularly abundant on the 

 shores of North-West Europe (France, Germany and the 

 British Isles). 



Cancer pagurus, the edible crab, has been chosen as 

 the subject of the present memoir partly on account of its 

 economic importance, and also because, as a type for 

 dissection, it is easily procurable and is of a convenient 

 size. The account given below, however, may be applied 

 with very few alterations to any of the brachyurous 

 Decapod Crustaceans, such as the common shore crab 

 (Carcinus) or the swimming crab (Portunus). 



The edible crab is found in great abundance on the 

 coasts of the British Isles, especiall} T on those parts which 

 are rocky, and gives rise to an important fishing industry. 

 The large crabs live in fairly deep water, but the young 

 representatives of this species may be readily obtained 

 between tide-marks. Cancer is mainly carnivorous in its 

 habits and feeding. It is particularly fond of dead fish, 

 and it probably also feeds on other Crustaceans in a small 

 degree. There is, however, no evidence to show that it 

 has cannibalistic instincts. (For further particulars with 

 regard to habits, distribution, crab fishery, &c, see section 

 on Economics.) 



Cancer pagurus was first named by Linneus, who 

 established both the genus and the species. In his 



* The investigation has been assisted by a grant of £25 from the 

 Board of Agriculture and Fisheries, and the expense of producing the 

 lithographed plates has been met in part by a grant of £30 from the 

 " Treasury Grant for Eesearch " of the University of Liverpool. 



