228 PHILOSOPHICAL TRANSACTIONS. [aNNO 1758 



covered these worms, which form sponges in the 4 following species : 1 . Spongia 

 Americana tubo similis ; the tube-like sponge of Plumier. 2. Spongia Ameri- 

 cana longissima funiculo similis ; the cord-like sponge of Plumier. 3. Spongia 

 Americana capitata et digitata ; the Angered sponge of Plumier. 4. Spongia 

 Americana favo similis ; the honey-comb sponge of Plumier. 



These 4 kinds differ only 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 the same observations were made on them all. 



When a fresh sponge is squeezed, the mucilage from the interstices of the 

 fibres comes out frothy, by the mixture of the windings of its fibres : it always 

 issues forth with sand, or little parcels of sliells crushed by the sea. These fibres 

 which consist of the twisted doubles of the sponge, form as it were a labyrinth 

 filled with worms, which are easily crushed, and their juice is confused with the 

 mucilage ; but having carefully torn the sponges, and their gross fibres, Dr. P. 

 discovered the living worms. These species of sponge commonly grow on sandy 

 bottoms. At their origins is perceived as it were a nodule of sand or other 

 matter, almost petrified, round which the worms begin to work, and round 

 which they retire, as to their last seat or refuge ; where he had seen them play, 

 exercise themselves, and retire, by examining them with the microscope ; and 

 he had even made observations without its assistance. 



The worms he found in these kinds of sponges are about one-third of a line 

 thick, and 2 or 3 lines in length. They are so transparent, that one may 

 discern their viscera through their coverings and substance : the blood may be 

 seen to circulate, and all their parts to act. They have a conic figure, with a 

 small black head furnished with two pincers : the other extremity is almost 

 square, and much larger than the head. On the back may be seen 2 white 

 streaks or fillets, as if they contained the chyle : these 2 canals are parallel to 

 each other from the head to the other extremity, where they come together. 

 In the middle where the belly and viscera ought to be placed, a blackish matter 

 is perceivable, which has a kind of circulation : sometimes it fills all the body 

 of the worm, sometimes it gathers towards the head, or at the other end, and 

 sometimes it follows the motion of the animal. This vermicular motion or pro- 

 gression begins at the posterior extremity, and ends at the head, which is 

 pushed, and consequently advances forward. He kept these worms alive out of 

 the sponge, quite detached from it more than an hour; having examined them 

 thoroughly with a middling magnifier ; for a great magnifier would be the grave 

 of the insect. 



He was surprized, after having finished his observations, when he put them 

 near a piece of the fresh sponge, where the nests were moist, and from which 

 he had pulled them, to see them enter into them and disappear, being lost in 



