Scyphia. _Lign. 70, 72._--These spongites are of a tubular, fistulous, or cylindrical form, and terminate in a rounded pit; they are either simple or branched, and composed of a firm reticulated tissue; _Lign. 70, fig. 2, 5, 6_, and _Lign. 72, fig. 4_, are examples. The Upper Greensand at Folkstone and Dover abounds in a flexuous species, named Scyphia meandrina (_Morris_). Cnemidium (_Goldfuss_). _Lign. 70, fig. 7._--These sponges consist of a cluster of turbinated projections, having a central pit above, and being porous on the external surface, and radiated at the margin. The mass is dense and fibrous, and is traversed by horizontal canals, diverging from the centre to the circumference. [Illustration: Lign. 71. Fossil Sponge; _nat._ (_Chenendopora fungiformis._) _Greensand. Faringdon._] Chenendopora.[GX] _Lign. 71._--The species of porifera thus named are cyathiform, or cup-shaped; externally furrowed, mamillated, or lobed; internally smooth, and the surface covered with fine pores. The beautiful species figured (_C. fungiformis_) is abundant in the gravel-pits, and well known to the quarrymen as "petrified salt-cellars." [206] The Pictorial Atlas contains coloured figures of the following:-- Chenendopora fungiformis (_Michelin_), Pict. Atlas, pl. xliv. _fig._ 5: according to Mr, Morris. ------------ subplana (_Michelin_), ibid, pl. xliv, _fig._ 3. Scyphia articulata (_Goldfuss_), ibid, pl. xliii. figs. 7, 8, 9. ------- costata (_Goldfuss_), ibid. pl. xliv, fig, 1. Cnemidium rimulosum (_Goldfuss_), ibid, pl. xliv. _fig._ 3. [Illustration: Lign. 72. Fossil Zoophytes; _nat._ _Greensand. Faringdon._ Fig. 1.--Tragos peziza. 2.--Probably Chenendopora in a young state. 3.--Verticillipora anastomosans. 4.--Species of Scyphia. 5.--Tragos Faringdoniensis. ] Tragos. _Lign. 72, fig. 1._--These turbinated sponges are readily distinguished from the preceding, by the relatively large oscula, or open papillæ, disposed irregularly on the inner surface; as shown in the specimen, _fig. 1._ Their tissue is dense and fibrous. The fossil represented by _fig. 5_, though named Tragos by collectors, appears to differ in the structure of the inner surface from the type of this genus: it is a remarkably beautiful species.[207] [207] It may be convenient to distinguish it as _T. Faringdoniensis_. The base in all these Greensand sponges is flat and expanded; not fibrous and root-like, as in the spongites of the chalk previously described. Among the shingle at Brighton, Margate, Dover, Isle of Wight, &c. pebbles containing fossil sponges may frequently be discovered. When the flint nodule has been broken, and the calcareous particles of the inclosed zoophytes are washed away by the action of the waves, a delicate silicified tissue remains.[208] Many of the large solid pebbles, are portions of silicified sponges, and polished specimens are beautiful objects under the microscope.