FROM THE LOWER CHALK. 



203 



scutella depressa, 



hemispherica, 



discoidea canaliculata, 



Galerites Hawkinsii, 



discoidea cylindeica, 



Galerites cylindkicus, 



DiSCOIDEA CYLINDRICA, 



HEMISPHERICA, 

 CYLINDRICA, 



Woodward. Geology of Norfolk, p. 52, pi. v, 



%. 4, 1833. 

 Woodward. Idem, pi. v, fig. 5, 1833. 

 Agassis. Prodrome, Mem. Sc. Nat. Neuchatel, 



t. i, p. 186, 1836. 

 Besmoulins. Etudes sur les Ecbiiiides, p. 254, 



1837. 

 Agassiz. Echinid. foss. de la Suisse, Part I, 



p. 92, pi. vi, figs. 13—15, 1839. 

 Bujardin. Animaux sans Vertebres 2e ed., t. 



iii, p. 311, 1840. 

 Besor. Monogr.iphie des Galerites, pi. viii, figs. 



8—16, p. 58, 1840. 

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

 Morris. Idem. 

 Agassiz et Desor. Catal. rais. les Ecb. An 



Sc. Nat. 3e ser., t. vii, p. 147. 1847. 



— — Bronn. Index Palseontologicus, p. 429, 1848. 

 Galerites (discoidea) cylindricus, Forbes. Mem. of Geol. Surv., Decade 1, pi. viii, 



1849. 

 d'Orhigmj. Prod, de Pal. strat., t. ii, p. 178, 1850. 

 Quenstedt. Hand, der Petrefact., pi. xl, fig. 20, 



p. 583, 1852. 

 Gras. Catal. Ours. foss. de I'lsere, p. 43, 1852. 



— — Morris. Catal. Brit. Foss., 2 ed., p. 77, 1854. 



— — Pictel. Traite de Paleont., t. iv, p. 228, pi. 



xcv, figs. 9—12, 1857. 



— — Besor. Synopsis des fichinides Fossiles, p. 177, 



pi. xxix, fig. 12, 1857. 



— — Cotteau. Paleont. Fran^aise, Ter. Cret., t. vii, 



p. 28, pi. 1010 et 1011, 18(36. 



— — BeLoriol. Ours, de la Suisse, pi. xiii, fig. 14, 1873. 



Biapiosis. — Test large, sub-circular, slightly pentagonal ; upper surface hemispherical, 

 more or less elevated, regularly convex above, rounded vertically on the sides, and acutely 

 angular at the border ; base nearly flat, marked by impressions which correspond to the 

 internal carina ; ambulacra one third the width of inter-ambulacra ; mouth-opening 

 central, decagonal ; vent small, oblong, basal, midway between the peristome and border. 



Dimensions. — a. Height, one inch and four tenths ; latitude, two inches and one tenth, 



B. Height, one inch and eight tenths ; latitude, two inches and two tenths. 



Description. — Whether this' common Chalk Urchin was known to Leske or not is 

 difficult to decide. My friend Professor Desor considers the notice on Echinus quater- 

 fasciatus to refer to this species ; but a careful examination of Leske's figures leads me to 

 the conclusion that the mouth figured by that author in his PI. xlvii represents some 

 ■species of the genus Echinoconus rather than a Discoidea, for they show no trace of 



discoidea cylindrica, 

 Galerites cylindricus, 



Discoidea cylindrica, 



