FROM THE UPPER GREENSAND. 201 



Galerites hemisph^eeicus, Grateloup. Mem. les Oursins Fossiles, p. 55, 1836. 



— sxTBCCULUs, Besmoulins. fitudes sur les Echinides, p. 254, 1836. 

 DiscoiDEA STJBUCULUS, Besor. Monogr. des Galerites, p. 54, pi. vii, figs. 5 — 7, 



1842. 



— — Morris. Catalogue of British Fossils, p. 52, 1843. 



— — Agassi: and Desor. Catal. rais. des Ech., Ann. Sc. Nat. 



3e serie, t. vii, p. 146, 1847. 



— — A. Gras. Oursins fossiles de I'lsere, p. 44, 1848. 



— — Bronn. Index Palseontologicus, p. 430, 1848. 

 Galerites subuculus, Forbes. Mem. Geol. Surv., Dec. 1, pi. vii, 1849. 

 DiscoiDEA SUBUCULUS, d'Orbigny. Prod, de Pal. Strat., t. ii, p. 179, 1850. 



— — Sorignet. Oursins fossiles de I'Eure, p. 39, 1850. 

 Galerites subuculus, Forbes in Dixon's Geology of Sussex, p. 341, 1852. 

 DiscoiDEA SUBUCULUS, Forbes in Morris's Catalogue of Brit. Fossils, 2ud ed., 



p. 77, 1854. 



— — Desor. Synop des Echinides Foss., p. 1/6, pi. sxiv, 



fig. 1, 1857. 



— — Cotteau and Triger. Ecliinides Foss. de la Sarthe, 



p. 170, pi. xxiv, fig. 12, 1859. 



— — Cotteau. Paleontologie Fran^aise, Ter. Cretace, t. vii, p. 



23, pi. 1009, fig. 8—16, 1864. 



— — Be Loriol. Oursins de la Suisse, pi. xiii, fig. 15, 1873. 



Dict(/)iosis. — Test small, circular, or slightly pentagonal ; upper surface inflated, more 

 or less conical ; under surface concave in the middle ; ambulacra forming five prominent 

 bands, composed of very narrow plates ; poriferous zones narrow, straight, holes 

 imigeminal in oblique pairs. Interambulacra wide, divided into three lobes by two sub- 

 central carinse, which rise from near the middle of the plates ; miliary zone concave, 

 depressed ; tubercles small, perforated, larger at the base ; on the sides there are two 

 regular, constant, carinal rows, and eight or ten less regular and inconstant ; at the base 

 the principal tubercles are arranged in concentric lines around the peristome. Surface of 

 all the plates covered with fine close-set granulations ; mouth-opening small, sunk in the 

 middle of a deep depression; vent infra-marginal, pyriform, midway between the 

 peristome and border, with the apex directed inwards. Apical disc small, prominent, 

 composed of five ovarial and five very small ocular plates. 



Bimensions. — Height, seven twentieths of an inch ; latitude, eleven twentieths of an 

 inch. The relative proportion of height to breadth varies considerably in different 

 specimens. 



Description. — A figure given by Plott^ in his ' History of Oxfordshire,' pi. viii, fig. 9, 

 and described as "another sort of Button-stone, sent me from Teynton, which I take to be 

 a mere production of nature, finely striated from the top, as I have seen some hair buttons, 

 as in Eig. 9, and may therefore be called Porpites .- except we should rather take it for a new 

 sort of EcJdnites not yet discovered, which is wholly left to the reader's choice." Martin 



> ' The Natural History of Oxfordshire,' ed. 1677, pi. viii, fig. 9, p. 139. 



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