AMPHITRITE. 993 
In the course of such an experiment, while the tube at first lies flat, 
the upper orifice is closed ; next the lower extremity of the Amphitrite 
is seen protruding at night, that great season of activity, and searching 
about by a short radius, as in quest of a proper spot for fixture. A small 
triangular silken sheath is soon after discovered attached to the glass, 
serving both as a new foundation, and to cover the naked part. In 
twenty-four hours the end of the tube is adhering, and in two days it 
begins to rise, but very slowly, and in a curvature, to which all have 
an ultimate tendency. Although the natural direction be upwards it is 
not vertical, perhaps from disturbing causes. Some even assume a com- 
pound curvature, as in the letter 8, which is less inconvenient than 
might be supposed, from the shortness of the body compared with the 
edifice. The specific gravity of both being much greater than that of 
the surrounding element, nor is there is any channel for the admission of 
air were it present, the mode of elevating from the extremity is not 
evident. Perhaps this, as well as closing the extremity, may result from 
air actually occupying the longitudinal sinus of the animal’s body. 
The welfare of the animal is dependent on fixture, otherwise it is 
totally helpless ; neither, until the extremity be secured, does the Amphi- 
trite usually venture to shew itself. Sometimes the renovated part of 
the sheath extended an inch or more at the bottom of the vessel, which 
being attained, all subsequent care seemed to be devoted to the oppo- 
site extremity about the orifice. 
An amusing resemblance to a bed of animated flowers may be readily 
obtained by the preceding expedient. Let a number of tubes be muti- 
lated at the lower extremity, and then tossed into a capacious vessel of 
sea-water ; in a few days, all will be found adhering by the lower extre- 
mity. When rising upwards, the tenants issuing forth to display their 
beautiful plumes, are beheld as enjoying their native element, or perform- 
ing their mechanical operations. 
In prosecuting a course of observations, it is frequently necessary to 
shorten tubes for accommodation in such vessels as may be at command. 
Separating a portion of the extremity while the animal is known to be 
