44 PHILOSOPHICAL TRAKSACTIONS. [aNNO 1763. 



covered with a skin, and furnisiied on 3 sides with tentacula or suckers: he says, 

 the fishermen call it penna del pesche de pavone, or the feather of the peacock 

 fish. To these he has added the alcyonium, called Manus marina; he calls it 

 Penna ramosa pinnis carenSj tentaculis in ramis positis; and in another place, 

 Penna exos. The figures of these pennatula, or sea pens, may be seen in the 

 works of Bohadsch, Linnaeus, and elsewhere. 



Mr. E. concludes with a short account of a new discovered species of penna- 

 tula, which his friend John Greg, Esq. of Charles Town in South Carolina, dis- 

 covered on that coast, and presented to him. This beautiftil purple animal is of 

 a compressed kidney shape. The body is about an inch long, and half an inch 

 across the narrowest part, it has a small roundish tail of an inch long, proceeding 

 from the middle of the body : its tail is full of rings, from one end to the other, 

 like an earth-worm ; and, along the middle of the upper and under part of it, 

 there is a small groove which runs from one end to the other. He examined 

 carefully the point of the tail, but could find no perforation in it ; which is 

 agreeable to what he has observed in the rest of this genus. The upper part of 

 the body is convex and near a quarter of an inch thick ; the whole surface of it 

 is covered over with minute yellow starry openings, through which are protruded 

 little suckers like polypes, each furnished with 6 tentacles or filaments, like 

 what we observe on some of the corals, and which seem to be the proper mouths 

 of the animal. The under part of the body is quite flat : this surface is full of 

 the ramifications of fleshy fibres, which, proceeding from the insertion of the 

 tail, as their common centre, branch out so as to communicate with the starry 

 openings on the exterior edge and upper surface of this uncommon animal. 



Fig. 3, pi. 1, is the kidney-shaped purple sea-pen from South-Carolina, in 

 its natural size. This upper part is full of starry openings, which send out 

 small suckers, like polypes, by which it feeds. Fig. 6 is the under part of the 

 same, with its ramifying fibres, that lead from the insertion of the stem, as 

 from a centre to the circumference, and correspond with all the starry openings 

 on the edge and back of it. Fig. 7 is a part of the exterior edge highly mag- 

 nified, to show the form of the starry openings and suckers, which consist of 6 

 rays and claws. 



Lir. A Letter from Mr. B. fVilson, F. R. S. to Mr. jEpinus. p. 436. 



This is a tedious and uninteresting dispute between Mr. ^pinus and Mr. 

 Wilson, concerning the nature of plus and minus electricity ; also the perme- 

 ability of glass to that fluid ; and on the electricity of the tourmalin. 



Lf^. On the Parallax of the Sun. By the Rev. Thomas Hornsby, M. A., 

 Savilian Professor of Astronomy, Oxford, and F. R. S. p. 467. 

 The quantity of the sun's parallax is of such importance, both to the theory 



