232 AMPHITRITE. 
the ribs, while some among them had four. The trowels likewise stretch- 
ed in a curvature from the neck, as if preparing for their proper func- 
tions. 
Above fifty days having now intervened from the period of mutila- 
tion, the body, somewhat reduced of its original dimensions, consisted of 
thirty or forty segments. Advancing reproduction, enlargement of the 
parts, their action on the accession of spots on the branchiz, shewed that 
nothing for the salubrity of the animal was wanting unless a proper posi- 
tion. In sixty-four days it appeared to be endowed with the essential 
requisites, for both organic and mechanical faculties, had it occupied a 
tube.—Plate XXX. fig. 11, slightly enlarged. It survived its separation 
from the original Amphitrite eighty-three days. 
It is truly remarkable that a fragment from the posterior extremity 
of such a creature as the Amphitrite, should generate a mutitude of 
organs belonging to the anterior portion, capable of such complex opera- 
tions. 
It is alike singular, and, at the same time unaccountable, that Na- 
ture should have denied this animal that alone whereby it may avail 
itself of this prerogative, the power of constructing any but its original 
tube. Even when entire, if once dislodged, it is apparently incapable of 
constructing the smallest portion of another dwelling, or that protection 
wherein its gifts can be turned to any use. When losing its earliest 
habitation it survives a considerable time, but always prostrate. Should 
it remain in the tube, it is secure notwithstanding privation of the plume, 
and if mutilated, it will regain another to be employed as the first. The 
regeneration of a plume by a fragment separating below, while confined 
in the tube, would be nugatory, as, while thus imprisoned, there is no 
scope for the exercise of its functions. A similar fragment free acquires 
a plume, but although so far privileged as to become entire, it remains 
naked and defenceless, equally incapable of sheltering itself by the exer- 
cise of its natural functions. Of what use, therefore, is this wonderful 
prerogative ? I am induced to conclude that there is here something un- 
discovered, some conditions whereby the peril may be averted. The 
