CEABS AND SIIKIMPS. 215 



exceeding!}^ 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. 



" Tlie 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 iind 

 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 tlian 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 Galatliear * 



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

 to a Megalopa / and this latter became after a short 

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

 long to the orde?' to wliicli the parent belongs ; but 

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

 form bore a close resemblance to that of the Sargasso 



* Rep. Cornw. Polyt. Soc. 1843. 



