240 AMPHITRITE. 



amidst them, the frill remaining with the mutilated trunk, shewed its 

 correspondence to the lunate portions. In twenty-six hours, the trunk, 

 now extending two inches, was invested by a fine slim silken sheath. 

 In fifteen days the rudiments of a regenerating plume rose, as several 

 shoots, an eighth of an inch long ; and in other three, specks on the back 

 of the ribs were discernible. Incipient fringes began to clothe the latter, 

 and in twenty-three days from the date of mutilation, the branchiae had 

 attained a third of the dimensions of those they were replacing. The 

 plume, also, with the regenerated antennulae, was half its proper diame- 

 ter. Accidental contamination of the water, at this time, occasioned 

 separation of the .new plume, as entire as that which it had succeeded. 

 The Amphitrite, however, weakened and died, tinging the surrounding 

 element green by its decay. 



A notable instance of reproduction succeeded, with a fragment half 

 an inch long, separating from the extremity of a specimen, recovered from 

 the sea on October 25. In three days a prominence was perceptible on 

 the anterior part, which, in other three, exhibited very short but dis- 

 tinct originating branchiae. This fragment invested itself with a sheath, 

 and continued always to repeat it when dislodged for observation. In 

 two months, the new parts proved a fine reproduction : the organs be- 

 hind the rib, at first mere prominences, were now acquiring their pecu- 

 liar figure, and the whole plume was about equal to the length of the 

 body when the animal was at rest. However, the extremities of the 

 ribs were still bare, and remained so five or six weeks from their origin. 

 -Plate XXXI., fig. 8 ; Plate XXXIII., the same, enlarged. 



The secretions of this specimen were very copious. Sometimes the 

 new sheath was invisible to the eye after it was formed. But the crea- 

 ture was apparently weakened by too frequent expulsion for the purpose 

 of observation, because new exudation necessarily followed privation of 

 its former dwelling. It survived seven months. Nothing could be more 

 satisfactory than the various illustrations afforded of the wonderful pre- 

 rogative of repairing lost parts, and the faculty of contributing to its own 

 security. 



In prosecuting this subject, about five lines, or a fourth of the body, 



