BRACHYURI. 155 



zontally, between the hind pair of Hmbs, by the yielding of the ligament 

 forming the hinge of the thorax and carapace, which admits the separa- 

 tion of these two portions, and allows escape from within of the con- 

 fined animal, clothed in its new integuments. 



The gaping edges or lips of the opening then close by their own 

 elasticity, while the old shell, emptied of its contents, appears to the 

 spectator as entire as ever. 



An absolute change has ensued, yet without any relation to the pro- 

 cess of metamorphosis, in the proper acceptation of that character. 



The spectator laeholds a new animal before him, distinguished by all 

 the parts of the individual with which he was previously so familiar. It 

 is alike perfect, the colours fresher and more vivid, either exactly the 

 same in quantity and proportion as originally, or pei'haps under some 

 variety and modification. But the creature is somewhat larger in this 

 its new garment than in the preceding shell, — nothing can be more ad- 

 mirable. 



After a brief interval of tranquillity this new animal moves, and 

 rests, and feeds as the old one ; I should rather say as when invested by 

 the old integument, for it is only the coveriiu], not the actual crcaf//re 

 itself, which is regenerated. 



It is not enough, however, that the change is effected once. It must 

 be repeated again and again, — as often as additional increment requires 

 additional space for the contents. 



I cannot affirm at what period exuviation commences, or when it 

 ceases, how often the shell is generated, or whether throughout the con- 

 tinuance of life. At a very early age it becomes indispensable, and it is 

 frequent. But later shells seem to subsist A'ery long, as is evident by the 

 quantity of animal and vegetable parasites investing them, doubtless the 

 growth of years. 



To follow the course of this remarkable process is extremely inte- 

 resting, and I acknowledge, that, being wholly unexpected, the first time 

 of its occurrence I witnessed it -with great surprise. 



I had preserved a reddish middle sized specimen for several months, 

 which became very tame and familiar, Plate XXXIV. fig. 5. The heat 



