246 AMPHITRITE. 
warts or prominences occupied their place, though I cannot speak con- 
fidently of the fact. 
From the long luxuriant fringes and incurvature of the branchie, 
the expanded plume resembles the double corolla of a fine flower. 
A transparent, tubular, thick gelatinous mass constitutes the dwell- 
ing of this animal, of very different appearance from the receptacles of 
the two preceding species. It has none of the regular form belonging to 
either. The side is not under an eighth of an inch in thickness, or once 
and a half the diameter of the body, and sometimes more ; it also ex- 
ceeds the length of the body considerably. It is originally quite diapha- 
nous and invisible, free of all adventitious matter, and seems entirely the 
product of an animal secretion. Sometimes it has been seen of a slight 
silky aspect, but it may almost always be compared to a gelatinous mass, 
which is affixed to an extraneous substance. 
The tenants of two such tubular habitations, each with a wide ori- 
fice, having been dislodged, they speedily generated a quantity of the 
most transparent jelly. But their plumes becoming mutually entangled 
from want of room, one of the specimens was transferred to a short glass 
tube, suspended in a different vessel. Here. it formed itself a copious 
covering in a week or less, apparently filling the cavity ; and, in time, 
the jelly projected beyond the mouth of the tube. At length, when the 
animal rose upwards, the jelly rose along with it, as much as nine lines 
above the edge of the orifice of the glass tube. Along with the expan- 
sion of the plume, the centre of the gelatinous matter expanded also ; 
on the other hand, as the plume contracted the diameter of the jelly 
contracted ; and if the animal sunk, the tubular orifice was depressed 
along with it and closed. All this gelatinous substance could not be 
under ten or twelve times the weight of the tenant ; yet, from excessive 
transparence, it then proved impossible to determine the precise outline 
of the jelly, nor until slightly darkened beyond the glass tube, when it 
appeared conical. ; 
If this tube, withdrawn from the water, be inverted, the jelly ad- 
hering within it hangs down from the orifice like a compact tenacious mass. 
