VOL. L.] PHILOSOPHICAL TRANSACTIONS. 227 



reddish juice passes out, carrying it to a fringed body like a mesentery ; and it is 

 there the purple juice is brought to perfection; and afterwards goes to a long 

 sac lying under a kind of horny plate, not like the bone of the cuttle-fish, but 

 like the bone of the sepia or little cuttle-fish, which we call le couteau. This 

 bone or horny substance is transparent, and is of a triangular figure, or ap- 

 proaching the form of a bivalve shell. On the right side it is fastened by a strong 

 cartilaginous muscle, which binds it to the body of the animal ; and on the left 

 it is open and detached, and easy to be pulled up : then it is easy to see under- 

 neath both the mesenteric body, and the tube or reservoir of the purple juice. 

 This bone or horny plate is covered by a loose membrane, which is by no means 

 attached to it, but capable of being filled and inflated with water or wind. The 

 whole is covered with two membranes, which are continuations of the fiesh of 

 the fish's body : the membranes are loose, and larger than are necessary to the 

 bone : they are wrinkled or rumpled over one another to cover the whole, and 

 to defend the bone and viscera from all kinds of pressure ; but they are ready to 

 stretch from each other, and leave the parts destined for the purple juice un- 

 covered. They begin a little under the neck, and extend in the female animal 

 to the tail, which is flat ; and in the male they do not go so low, but end at 

 some distance from the tail. The females are oviparous ; for eggs are found in 

 the grand cavity, at the side of the pancreatic body. 



It has already been said, that when the animal is touched he makes himself 

 round, and throws out his purple juice, as the cuttle-fish does his ink. This 

 juice is of a beautiful deep colour : it tinges linen, and the tincture is difficult to 

 get out. It remains at present to try if we can collect a sufficient quantity of 

 this juice, and to find a means of preserving the tincture ; which would then be 

 certainly of great value. 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 in- 

 terstices of the fibres is dissipated, and the dry fibres contract: which clearly ap- 

 pears from dissecting them. 



LXXVIIL New Observations on the Worms that form Sponges.* By J. A. 

 Peyssonel, M. D., F.R.S From the French, p. SQO. 

 The existence of the nests of corallines and lithophyta, and the mechanism 

 of their polypi, made Dr. P. 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 he had not yet seen nor discovered the insects, nor ob- 

 served their work. Sponges appeared only as skeletons : but at length he dis- 



• It is necessary to observe here, that Dr. Peyssonel's notion of the formation of sponges by 

 worms is totally erroneous, and that sponges constitute a peculiar genus of Zoophytes. 



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