21G 



EVENINGS AT THE MICROSCOPE. 



Crabs {Grapsidd) ; for tlie sliield, instead of being 

 large and arched in front, and narrowed behind, was 

 nearly square, while the front was (taking in the eyes) 

 almost strai£>:ht, the lateral angles much advanced. 



This Crab, however, was still very minnte ; and 

 many slonghings w^ere before it. In the course of these 

 it was destined gradually to attain not only the dimen- 

 sions of its parents, but also their form. This, how- 

 ever, would be matter of development, rather than 



THIRD STAGE OF SnOnE-CRAB. 



T>-etamorphosis : the lateral outlines of the shield would 

 more and more approach each other behind, while the 

 series of points that now belonged to these lateral out- 

 lines would become thrown into the front margin, 

 which would by degrees assume an arched form, as 

 you may see in this figure of the adult Crab. 



Though I cannot at this moment show you speci- 

 mens of the Carcinus in its earlier stages, yet I have 

 here a good number of the Zocas of one of those inter- 

 mediate forms which are the connecting links between 

 the Crabs and Lobsters : — I mean Galathea. The 

 adult animal is of a broad squat form, something like 

 wdiat you might suppose a Lobster to be, if it had been 

 flattened between two stones, without being actually 



