The Kentish rag contains irregular ramose spongeous bodies, which belong to this group of porifera; and Mr. Bensted has discovered in his quarry, near Maidstone, numerous remains of a polymorphous lobed zoophyte, having a porous structure beset with spicula. In the Firestone of Southbourne, Steyning, and Bignor, in Sussex, I have observed large pyriform and subcylindrical Siphoniæ. The organization of all these zoophytes was evidently adapted for the imbibition and circulation of sea-water, in a more perfect and definite manner than in the irregular simple sponges. Flint-pebbles inclosing remains of Siphoniæ abound on the Sussex coast, especially in the shingle near Brighton, having been washed out of the chalk cliffs. There were several chalk-pits in Edward-street, (now, I believe, filled up and the area built upon,) in which every flint enveloped a sponge or siphonia; many specimens were mineralized by pyrites and beautifully exhibited the internal structure of the originals. Siphonia Morrisiana. _Lign. 69, fig. 3._--A polished slice of a pebble from Brighton, whose markings are derived from the transverse section of an undescribed zoophyte is figured, _ante_, p. 224: though scarcely more than half the diameter of the original is preserved, yet its structure is well shown; the centre is occupied by numerous parallel openings, the sections of longitudinal tubes, and is surrounded by a broad zone of spongeous tissue. I have seen many examples of this beautiful fossil, set for brooches in the jewellers' shops in the Isle of Wight, and at Brighton.[211] [211] The specific name is in honour of John Morris, Esq. F.G.S. the author of the "Catalogue of British Fossils," whose important services to Palæontology and Geology it is gratifying thus to acknowledge. There are coloured figures of Siphonite in Pictorial Atlas, pl. xxxix. _fig._ 9; pl. xlii. _fig._ 3, 4, 5, 7, 12, and 13; pl. xliii. _fig._ 6. Siphoniæ (chiefly _S. pyriformis_) are abundant in the Upper Greensand, near Farnham in Surrey, but their tissues are saturated with phosphate of lime, instead of silica as is ordinarily the case; the entire sponge usually contains between 50 and 60 per cent, of phosphate: hence these fossils have, of late, been in great request for manure.[212] [212] Mr. Payne, of Farnham, a distinguished agriculturist, has largely made use of them, both in the natural state and treated with sulphuric acid. The Firestone strata on St. Catherine's Hill, Isle of Wight, have been dug for a like purpose. See an "Account of the Phosphate Diggings," in my Isle of Wight, Second Edition, p. 448. [Sidenote: CHOANITES KÖNIGI.]