38 FOSSIL ASTEROIDEA. 



2. Metopasteb Mantelli, Forbes, sp. PI. XIII, figs. 2a — 4b. 



Pentagonastee SEMILT7NATUS, Parkinson, 1811. Organic Eemaius of a 



Former World, vol. iii, p. 3, 

 pi. i, tig. 1 (non Linek). 

 ? G-ONIASTEE SEMILTJNATA, , Mantell, 184J. The Medals of Creation, 



London, vol. i, p. 338, Hgn. 75 

 {lion Liuck, ? nee Parkinson). 



GoiTiASTEE (GONIODISCTJS) Mantelli, Forles, 1848. Memoirs of the Geological 



Survey of Great Britain, 

 vol. ii, p. 472. 



— — — Forbes, 1850. In Dixon's Geology and 



Fossils of the Tertiary and 

 Cretaceous Formations of 

 Sussex, London, 4to, p. 332, 

 pi. xxiii, figs. 11, 12. 



— — — Morris, 1854. Catalogue of British Fos- 



sils, 2nd ed., p. 81. 

 ? — Mantelli, Mantell, 1854. The Medals of Creation, 



London, 2nd ed., vol. i, p. 307, 

 lign. 98. 



AsTKOOONiTJM MaNTELli, Dujardin and Hupe, 1862. Hist. Nat. 



Zooph. Echin. (Suites a 

 Buffon), p. 399. 



GoNiASTEE (GoNiODiscus) Mantelli, Forbes, 1878. In Dixon's Geology of Sussex 



(new edition, Jones), p. 366, 

 pi. xxvi, figs. 11, 12. 



Body of medium or rather small size. General form depressed. Abactinal 

 surface flat, with the area circumscribed by the supero-marginal plates plain and 

 rather sunken below the level of the median convexity of the border formed by 

 these plates. Actinal surface plain, or may be a little convex in consequence of a 

 tendency to a slight upturning of the rays in some examples. Marginal contour 

 pentagonal, with sides faintly lunate, or in small examples they may be almost 

 straight. The major radius measures scarcely one-third more than the minor 

 radius. Margin rather thin, but well rounded. 



The supero-marginal plates are four in number, counting from the median 

 interradial line to the extremity, or eight from the tip of one ray to the tip of 

 the adjacent ray, exclusive of the odd terminal or "ocular" plate in each case. 

 In one example, which is figured by Forbes in Dixon's ' Geology of Sussex,' 



