CEABS AND SHEIMPS. 211 



tioDS, which had previously been regarded as types, not 

 of genera only, but of different families ; and both strik- 

 ingly dissimilar from the group to which, in its perfect 

 state, it belongs." 



I have not myself examined the transformations of 

 this species ; but, as they have been well worked out, 

 and as the animal is so abundant everywhere on the 

 coast that you may easily verify what has been ob- 

 served, I will cite you the elaborate account of Mr. E. 

 Q. Couch of Penzance, who has investigated the subject 

 with great skill, zeal, and success. 



Having procured some specimens of the Shore-crab 

 laden with eggs, just ready for shedding, he goes on to 

 say, — "these were transferred to captivity, placed in 

 separate basins, and supplied with sea-water ; and in 

 about sixteen hours I had the gratification of finding 

 large numbers of the creatures alluded to above swim- 

 ming about with all the activity of young life. There 

 could be but little doubt that these creatures were the 

 young of the captive Crabs. In order, however, to se- 

 cure accuracy of result, one of the Crabs was removed 

 to another vessel, and supplied with filtered water, that 

 all insects might be removed ; but in about an hour the 

 same creatures were observed swimming about as be- 

 fore. To render the matter, if possible, still more cer- 

 tain, some of the ova were opened, and the embryos ex- 

 tracted ; but shortly afterwards I had the pleasure of 

 witnessing, beneath the microscope, the natural burst- 

 ing and escape of one precisely similar in form to those 

 found so abundantly in the water. Thus, then, there is 

 no doubt that these grotesque-looking creatures are the 

 young of the Carcinus mosnas ; but how different they 

 are from the adult need hardly be pointed out any fur- 



