32 FOSSIL ASTEROIDEA. 



GoxiASTEB (GoNioDisctis) PAHKiNSoia, Forhes, 1848. Memoirs of the Greological 



Survey of Great Britain, vol. ii, 

 p. 472. 



— — EECTiLiNEns, McCoy, 1848. Ann. and Mag. Nat. 



Hist., ser. 2, vol. ii, p. 408. 



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



Fossils of the Tertiary and Cre- 

 taceous Formations of Sussex, 

 London, 4to, p. 332, pi. xxi, 

 figs. 10, 11 ; pi. xxii, figs. 5 — 7. 



— — — Morris, 1854. Catalogue of British 



Fossils, 2nd ed., p. 81. 



— — EECTiLiNETJS, McGoy, 1854. Contrib. Brit. Pal., p. 55. 



— — — Morris, 1854. Catalogue of British 



Fossils, 2nd ed., p. 81. 

 AsTEOGONirAi Paekiusoni, Dujardin and Rupe, 1862. Hist. Nat. 



Zooph. fichin. (Suites a Buffou), 



p. 399. 

 — fiECTiLiNEUM, Dujardin and Rupe, 1862. Ibid., p. 400. 



Goniastee (Goniodiscus) Paekinsoni, Forbes, 1878. In Dixon's Geology of 



Sussex (new edition, Jones), 



p. 365, pi. xxiv, figs. 10, 11; 



pi. XXV, figs. 5 — 7. 

 Pentagonastee EECTILINETJS, Woods, 1891. Catalogue of the Type 



Fossils in the Woodwardian 



Museum, Cambridge, p. 36. 



Body of medium size. General form depressed. Abactinal surface flat, with 

 a tendency, however, for the extremity of the rays to be slightly upturned ; as 

 found in the fossil state the area occupied by the abactinal plates is usually at a 

 lower level than the marginal plates, which leads to the assumption that the 

 abactinal floor had collapsed or fallen to a certain extent on the death of the 

 animal. Actinal surface slightly convex. Marginal contour pentagonal, with 

 slightly lunate sides, the curvature being often flattened at right angles to the 

 median interradial line. The major radius measures about one-third more than 

 the minor radius, and frequently less than one-third ; the rays are consequently 

 very feebly produced. Margin thick and 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. 

 They form a broad border to the abactinal area of the disk of uniform breadth 

 throughout, which measures about 9 mm. at the median interradial line in an 

 example whose minor radius measures 30 mm. Excepting the ultimate paired 

 plates all the supero-marginal plates are of equal size, the breadth being about 



