When the fish is boiled, or put into spirits, it shrinks up, and loses two thirds of its size; because all the water, which is in the interstices of the fibres, is dissipated, and the dried fibres contract: which clearly appears from dissecting them.
Peyssonel.
Dated at Guadaloupe, 20 Mar. 1757.
LXXVIII. New Observations upon the Worms that form Sponges. By John Andrew Peyssonel, M. D. F.R.S. Translated from the French.
Read Feb. 23, 1758.
THE existence of the nests of corallines and lithophyta, and the mechanism of their polypi, made me conjecture, that it was the same with respect to sponges; that animals, nested in the interstices of their fibres, gave them their origin and growth: but I had not yet seen nor discovered the insects, nor observed their work. Sponges appeared to me only as skeletons: but I at length discovered these worms, which form sponges, in the four following species:
- 1. Spongia Americana tubo similis; The tube-like sponge of Plumier.
- 2. Spongia Americana longissima funiculo similis; The cord-like sponge of Plumier.
- 3. Spongia Americana capitata et digitata; The fingered sponge of Plumier.
- 4. Spongia Americana favo similis; The honeycomb sponge of Plumier.
These four kinds only differ in form: they have the same qualities, are made by the same kinds of worm, and what may be said of the one agrees exactly with all the rest; for I made the same observations upon them all.
They may be classed among the spongiæ hyrcinæ, so called by J. Bauhin, because of the roughness of their fibres, by a metaphor, from pieces covered with mud; or among those called by Pliny tragos, or aphysiæ, being foul, and difficult to cleanse; and may take the name, which Father Plumier has given them, drawn from their figure.
These four kinds of sponges are composed of hard, firm, dirty fibres, sometimes brittle; separated one from another, having large hollows, or cylindrical tubes, dispersed thro’ their substance. These tubes are smooth within. The interstices of their fibres are filled with a mucilaginous gluey matter, when the sponge is just taken out of the sea. The mucilage is of a blackish colour, soon putrifies in the water, or falls into dust when dried in the sun.