258 PHILOSOPHICAL TRANSACTIONS. [aNNO 1765. 



he favours the r. s. with a letter dated from thence, March 1, 1757. Vid. Phil. 

 Trans, vol. 50, p. 592,* where he has given a particular account of the animal 

 which he assures us forms the sponges. There is something so remarkahle in 

 his description of the animal, and its manner of fabricating the sponge, that it 

 is necessary to quote the most striking parts, in order to submit the probability 

 of it to the R. s. 



He takes notice, " that the same kind of animal forms the 4 principal species 

 of sponges described by Father Plumier, as the tube sponge, the cord-like sponge, 

 the digitated sponge, and the honeycomb sponge. These sponges, he says, con- 

 sist of hard firm fibres, twisted about in doubles, and the interstices filled with 

 a mucilaginous gluey matter, having large hollows, with cylindrical tubes, dis- 

 persed through their substance, forming a kind of labyrinth filled with these 

 worms." He says, he has observed, " that the sponges begin to be formed ott 

 a nodule of petrified sand or other like matter, round which the worms begin to 

 work, and round which they retire as to their last seat of refuge." He then 

 proceeds to give a description of them, which is, " that they are -J- of a line 

 thick, 2 or 3 lines long, of a conic figure, with a small black head furnished with 

 2 pincers; the other extremity is square, and much larger than the head; their 

 motion begins at the tail, and ends at the head ; they are so transparent, that the 

 circulation of the blood may be perceived; and where the viscera should be, 

 there is a kind of circular motion of a blackish matter moving to and fro in the 

 animal. He says, he has kept them alive more than an hour out of the sponge, 

 and, which is very singular, when he put them near a piece of fresh sponge, 

 where the nests were moist, and from which he had before pulled them, he saw 

 them enter and disappear. He goes on to tell us, that these worms have no par- 

 ticular lodge; that they walk indifferently into the tubular labyrinth; so that, he 

 says, without offence to Pliny and other nauralists, he does not see that it is in 

 their power to dilate and contract the bodies of sponges, which always remain in 

 the same state of magnitude, without being sensible to the touch, being an inani- 

 mate body, all the sensitive life belonging to the worms. He then tells us, that 

 with the slaver or juice they deposit, they make the sponge increase or grow, as 

 bees and wasps, and especially the woodlice of America, increase their nests 

 and cells." 



This account appearing so contrary to the proceeding of nature in-the forma- 

 tion of the other kindred marine bodies, called zoophytes, such as corals, kera- 

 tophytons, and alcyoniums, particularly the last; Mr. E. was determined to find 

 out the truth of this extraordinary discovery, which he found had been thought 

 worthy of a place in the Philos. Trans. Accordingly in the year 1762, when at 



* Page 227, vol. xi, of these Abridgments. 



