AMPHITRITE. 225 



From the preceding detail, it may be collected how much the wel- 

 fare of the Amphitrite depends exclusively on the preservation of the 

 branchiae ; and that the vital and mechanical functions cannot be other- 

 wise discharged without imminent peril or exposure. 



But Nature has here conferred one of her most valuable preroga- 

 tives, as on some other of the humbler tribes, as may be illustrated by 

 impressive examples. 



In the end of April 1825, several specimens having been recovered 

 from the sea, all were found to be mutilated and wanting the head. One 

 of the largest was cleansed of parasite matter, and lodged in a tall glass jar, 

 three inches and a half wide, the largest then at command, after shorten- 

 ing the higher and lower extremities of the tube for adapting it to the 

 dimensions of the vessel. The animal not only occupied all the residue, 

 now exceeding a foot, but the lower extremity stretched an inch beyond 

 the orifice, from which, however, it withdrew in two or three days, when 

 secured by the peculiar adhesion previously explained. 



Cramped for room in its tubular mansion, the Amphitrite repeatedly 

 protruded its mutilated stump from above, when the trowels appeared 

 in feeble, and necessarily inefficient operation. In eight days, what 

 during the interval seemed a cluster of low irregular prominences, be- 

 came better defined as appurtenances of the mouth ; and ten of the 

 shortest filaments behind then denoted the rudiments of the two fans. 

 The original plume, composed of numerous branchiae, had been found 

 among the heterogeneous matter always accompanying the recovery of 

 such creatures, and on cutting it asunder, the antennular organs were 

 recognised in their proper place. 



After several days concealment, momentary exhibition of the stump 

 shewed rapid reproduction, which, in its progress, might raise the reno- 

 vating plume too high for the vessel. The tube was therefore curtailed 

 of two inches of the upper part as its tenant retreated below. 



In another week about twenty-five regenerating branchiae were dis- 

 covered in each fan, the longest of them extending towards four lines, 

 and also rising in regular proportion from the side next the trowels, 

 being there scarcely perceptible. Many were simple ribs like hairs ; the 



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