f 59 1 ] 
They may be clafled among the fpongue hyrcince , 
fo called by J. Bauhin, becaufe of the roughnefs of 
their fibres, by a metaphor, from pieces covered 
with mud ; or among thofe called by Pliny tragos> 
or aphfice , being foul, and difficult to cleanfe ; and 
may take the name, which Father Plumier has given 
them, drawn from their figure. 
Thefe four kinds of fponges are compofed of hard, 
firm, dirty fibres, fometimes brittle ; Separated one 
from another, having large hollows, or cylindrical 
tubes, difperfed thro’ their fubfiance. Thefe tubes 
are fmooth within. The interfiles of their fibres are 
filled with a mucilaginous gluey matter, when the 
fponge is juft taken out of the fea. The mucilage 
is of a blackifh colour, foon putrifies in the water, 
or falls into duft when dried in the lun. 
When a frefh fponge is fqueezed, this mucilage 
comes out frothy, by the mixture of the windings 
of its fibres : it always ifiues forth with fand, or little 
parcels of (hells crufhed by the (la. Thefe fibres, 
which confift of the twifted doubles of the fponge, 
form as it were a labvrinth filled with worms, which 
are eafily crufhed, and their juice is confuted with 
the mucilage ; but having carefully torn the fponges, 
and their grofs fibres, I difcovered the living worms, 
fuch as I (hall mention hereafter. 
Thefe fpecies of fponge commonly grow upon 
fandy bottoms. At their origins we perceive, as it 
were, a nodule of fand, or other matter, almoft pe- 
trified, round which the worms begin to work, and 
round which they retire, as to their laft feat or refuge j 
where I had the pleafure of feeing them play, exer- 
cife themfelves, and retire, by examining them with 
