224 AMPHITRITE. 
above, may be always done with indemnity. If pressure below be em- 
ployed, it must be very gentle. 
This artificial dwelling, or tube, seems designed both for perma- 
nent shelter, and as a place for immediate retreat from danger, because 
the animal always courts the light, and displays its plume when confi- 
dent of safety. 
Both the original aspect of the Amphitrite itself, and the mode 
whereby its dwelling originates, are exceedingly obscure. Accessions to 
the latter must depend for facilities in the presence of materials, when its 
progress is certainly much quicker than the organic increment of the 
occupant. A tube, sixteen inches long, sheltered an animal not above 
seven, though, perhaps, of considerable age. Here a broad coral ring, 
whereon several of the vermicular tribes had established their habitation, 
encompassed some of the lower parts of the edifice, while the white Lobu- 
laria loaded another portion ; and, chief of all, a grove of beautiful Ser- 
tulariz, investing the higher parts in great profusion. Specimens among 
them rose three inches high. Nothing but constant renovation of the 
native element, by submarine currents or otherwise, could have averted 
the consequences of the repeated decay concomitant on such a variety 
of animal matter. Naturalists, let it be repeated, probably misled by 
transient observation, are disposed to restrict the duration of the lower 
tribes to a term within the truth. Perhaps the Amphitrite ventilabrum 
is not one of the shorter-lived creatures. 
However expert in its natural state, the architect, if deprived of the 
tube, seems incapable of replacing it by any means. Yet it does not evi- 
dently suffer ; the plume is unfolded as usual; and smaller specimens 
have survived during weeks uninjured. 
The great timidity of this creature indicates the exposure to many 
enemies roaming through the wide expanse of the deep. Circumstances 
also tend to shew the hostility of one more invidious, the Gordius 
mavimus, Which might gain readier access but from closure of the orifice 
of the tube. Nevertheless, it probably does enter the dwelling to devour 
its tenant. 
