186 EVENINGS AT THE MICKOSCOPE. 



native pools, are, if possible, even more active than when 

 in confinement. Their swimming is produced by con- 

 tinued flexions and extensions of the tail, and by repeated 

 beating motions of their claws ; this, together with their 

 grotesque-looking forms, gives them a most extraordinary 

 appearance when under examination. As the shell be- 

 comes more solid they get less active, and retire to the 

 sand at the bottom of the vessel, to cast their shells and 

 acquire a new form. They are exceedingly delicate, and 

 require great care and attention to carry them through the 

 first stage ; for unless the water be supplied very fre- 

 quently 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 disappearance 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 antennsB. 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 proportions, and 

 is sometimes partially bent under the body, but is more 

 commonly extended. This form is as natatory as the 

 first. They are frequently found congregating 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 re- 

 sembles a Galathea."'* 



* " Rep. Cornw. Polyt. Soc.," 1843. 



