CEABS AND SHEIMPS. 215 



exceedingly delicate, and require great care and atten- 

 tion to convey them through the first stage ; for unless 

 the water be supplied very frequently and in great 

 abundance, they soon die. 



" The second form of transmutation is equally as re- 

 markable as the first, and quite as distinct from the 

 adult animal. In the species now under consideration 

 this second transformation is marked by the disappear- 

 ance of the dorsal spine ; the shield becomes flatter and 

 more depressed, the anterior portion more horizontal 

 and pointed, the three festoons having disappeared. 

 The eyes, from being sessile, are now elevated on foot- 

 stalks, the infra-orbital appendages become apparently 

 converted into antennae. The claws undergo an entire 

 revolution ; the first pair become stouter than the others, 

 and are armed with a pair of nippers," the others being 

 simple ; " but the posterior pair are branched near the 

 base, and one of the branches ends in a bushy tuft. The 

 tail is greatly diminished in its relative size and propor- 

 tions, and is sometimes partially bent under the body, 

 but is more commonly extended. This form is as nata- 

 tory as the first. They are frequently found congregat- 

 ing around floating sea-weed, the buoys and strings of 

 the crab-pot marks, and other floating substances, both 

 near the shore and in deep water. Their general form 

 somewhat resembles a Galathea." * 



Thus under Mr. Couch's eye the Zoea had changed 

 to a 3fegalopa / and this latter became after a short 

 time a Crab, in which were all the characters that be- 

 long to the order to which the parent belongs ; but 

 not those of the genus, nor even of the family. Its 

 form bore a dose resemblance to that of the Sargasso 



* Rep. Cornw. Polyt. Soo. 1843. 



