VOL. LV.] PHILOSOPHICAL TRANSACTIONS. 26 1 



very judiciously says, these are not the fabricators, but the inhabitants; and al- 

 lows the alcyonium to be of animal origin, in which he says he has discovered 

 evident marks of sensation. As to the 2d doubt, it may be observed by the 

 curious inquirer into nature, that the same property of inclosing extraneous sub- 

 stances is common to the whole class of zoophytes, as they grow up, from the 

 sponge to the red coral. In order to prove this, Mr. E. had various specimens, 

 as well of sponges as keratophytons and corals, with different bodies inclosed in 

 them, both animal and vegetable. He had specimens where even the red coral 

 encloses the white coral, and the white the red: with many keratophytons, that 

 have enclosed small roundish shells of the barnacle tribe, thought by some super- 

 ficial inquirers into nature (who would have them to be vegetables) to be the fruit 

 of the keratophytons. 



Explanations of the Figures, which are in plate 7. — a is an irregular piece of 

 the crumb of bread sponge, found at Pagham on the sea coast of Sussex ; aa 

 represent the papillae, through which the sponge receives and discharges the 

 water: this, when recent, is of a fine orange colour. — Fig. b is the branched 

 English sponge; at bb, along the edges, and on the surface of the branches, are 

 rows of small papillary holes, through which the animal receives its nourish- 

 ment. — Fig. c represents the downy branched English sponge found on the Sussex 

 coast; this is covered over with a fine down so close, that it hides the many small 

 holes that are on its surface. — Fig. d and e, the perpendicular and horizontal 

 sections of the common officinal sponge. — Fig. p is the cock's comb sponge, 

 taken off the rocks at Hastings in Sussex, and viewed while alive in sea water. 

 The other sponges represented here, are introduced to show the variety of forms 

 these animals appear under in different parts of the world. — Fig. g is a branched 

 tuberculated sponge from Cape Coast Castle in Africa. Fig. g represents the 

 appearance of the tubercles in their dried state, when magnified. This sponge 

 approaches very near to the figure of the corallium album porosum maximum of 

 Sir Hans Sloane, see the Hist, of Jam. vol. i, tab. 18, fig. 3, and of the porus 

 albus erectior ramosus tuberculis crebris sursum spectantibus of Morison. See 

 Hist. Ox. p. 3, sect. 15, tab. 10, fig. 3. — Fig. h is a sponge from Stavanger on 

 the coast of Norway; this may be called the sea-fan sponge, from its great like- 

 ness to the keratophyton of that name; all its pores are surrounded with small 

 spiculse, which, from their minuteness, could not be well represented in the 

 drawing. The dichotomous branched sponge at fig. i, is of a firm but elastic 

 texture, very full of small holes, guarded by minute spines; this was found on 

 the coast of Norway, and presented by Peter Collinson, Esq., f.r.s. 



XXXII. Extract of a Letter from Dr. John Hope, Prof, of Medicine and 

 Botany, Edinburgh, to Dr. Pringle. Dated Edinb. Sept. 1A, 1765. p. 2Q0. 

 In autumn 1763, Dr. H. received from Dr. Mounsey the seeds of the rheum 



