THE ARCHIPELAGO OF CHAUSEY. 53 



what unexpected wonders were revealed to my sight, 

 when, by means of the scalpel and microscope, I 

 penetrated to its inmost organism ! In this animal, 

 the walls of whose body Avere scarcely one-fiftieth of 

 an inch in thickness, I could trace seven distinct 

 layers of tissue, a skin, muscles, and membranes. I 

 perceived that the petal-like tentacles were furnished 

 with cupping glasses, by which the Synapta was 

 enabled to ascend the polished surface of a glass ; 

 and finally I discovered that this animal, which 

 appeared destitute of every means of attack or 

 defence, was actually protected by a kind of mosaic, 

 formed of small calcareous shields, bristling with 

 double hooks, whose points, serrated like the arrows 

 of the Carib, had even penetrated the skin of my 

 hands. 



After having preserved several living Synaptas 

 for some time in a vase of sea- water, I observed that 

 they underwent a process of self-consumption. 

 First they distended the posterior portion of their 

 bodies by suffering the fluid to accumulate there, 

 which incessantly circulates between the intestine 

 and the integuments; by this means a stricture was 

 speedily produced, and the final separation suddenly 

 effected. Scarcity of food seemed to be the sole 

 cause of these spontaneous amputations. It almost 

 appeared as if the animal, feeling that it could not 

 supply the whole of its body with nourishment, 

 suppressed those parts which it might cost the 

 entire organism too much to maintain ; somewhat on 

 the same principle as that by which all useless 

 mouths are banished from a besieged town. This 



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