GREAT CRAH. f>3 



the spring and summer, as is the case with so many other 

 species. 



It was in the month of June, 1826, that Mr. J. V. 

 Thompson* "had the good fortune to succeed in hatching 

 the ova of the common crab," and thus, by perfect and 

 satisfactory observation, demonstrated the theory which 

 his investigation of Zoea had already suggested to his 

 mind, of the true metamorphosis of the Crustacea ; a dis- 

 covery which may rank amongst the most interesting and 

 important that have been made within the sphere of the 

 sciences of observation, not only in the present, but in any 

 previous age. The extreme difficulty of preserving these 

 little animals alive, and ensuring them a supply of their 

 proper food, has prevented the observations of their subse- 

 quent growth from being so satisfactorily carried out as 

 could have been wished ; but the doctrine thus established 

 has been confirmed in so many instances by observations 

 on other species of Crustacea, that the metamorphosis of 

 these animals may now- be considered as a fixed and 

 incontrovertible truth. 



The fishery for these crabs constitutes an important trade 

 on many parts of the coast. The numbers which are 

 annually taken are immense ; and as the occupation of 

 procuring them is principally carried on by persons who 

 are past the more laborious and dangerous pursuits of 

 general fishing, it affords a means of subsistence to many 

 a poor man who, from age or infirmity, would be unable 

 without it to keep himself and his family from the work- 

 house. They are taken in what are termed " crab-pots ;" 

 a sort of wicker trap, made, by preference, of the twigs 

 of the golden willow, (Salix vitellina,) at least, in many 

 parts of the coast, on account, as they say, of its great 



* See his " Zoological Researches," No. I. p. 9. 



