220 AMPHITRITE. 
sive internal lining of gluten, much resembling the same that is used in 
the arts, and capable of resisting rude external impressions. Its obvious 
origin is an animal secretion, combined with mud or earthy matter. 
After several months preservation in a dry state, a portion of the tube cuts 
like very soft horn ; and the glutinous lining, half a line thick, yields in 
combustion the odour of burning horn, accompanied by slight foetor. 
It is evident that the edifice can advance only when the entire 
plume with the mechanical organization rises free above the orifice. The 
bottom of the funnel requires to be about twice the diameter of the tube 
above its edge, whence the tongue or scoop is always elevated for per- 
forming its functions. Perhaps this organ and the trowels may be found 
integral parts of the same apparatus. 
The office of the antennular prismatic spines in the centre of the 
funnel is obscure. Rising erect, and apparently for some peculiar func- 
tion during fabrication of the tube, particles of matter seem ascending in 
contact with them, and sometimes pouring like a stream from their 
points. 
The tenant seems totally dependent on the presence of mud for en- 
larging its habitation, and it is surprising how speedily a quantity ac- 
cumulates in the centre of the funnel previous to commencing its revo- 
lution, demitting the preparation between the trowels, and pasting it 
around the orifice. 
Surely the presence of the suspended muddy matter is very grateful 
and inviting. It seems to arouse the dormant faculties of the humble 
artists, and to excite their energy while lurking fora season within their 
tubes in languid quiescence. No sooner is the water rendered turbid, 
than they issue forth and begin their architectural preparations. 
Perhaps some secret necessity urges constant prolongation of the 
dwelling, whether for security, or for advancing increment. Should the 
animal be alarmed during its preliminary collections, it vanishes in a 
moment ; the muddy aggregate discharged by collapse of the branchie fall 
useless among the surrounding element. But if a feather, now dipped 
in mud, be first plunged among the water of another vessel, to separate 
the grosser parts, and afterwards in that which contains the Amphitrite, 
