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 branchie had 
attained a third of the dimensions of those they were replacing. The 
plume, also, with the regenerated antennule, 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 branchiz. 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 XX XIII, 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, 
