320 



HOLASTER 



HOLASTER SUBGLOBOSUf 



Cotteau et Triger. Ech. foss. de la Sarthc, p. 202, pi. 



xxxiii, figs. 7, 8, 1860. 

 Lory. Descr. dn Dauphine, pp. 350, 367, 1860. 

 Dvjardin et Hupe. Suites a Buffon, Echinodermes, 



p. 592, 1862. 

 Strombeck. Die Kreide bei LUneburg ; Zeitscb. deutsch. 



Gessell., 1863. 

 Cotteau. Catal. des Echin. de l'Aube, p. 39, 1865. 

 Ooster. Synopsis des Ecbin. Foss. des Alpes Suisses, 



p. 96, 1865. 

 Heer. Die Urwelt der Scbweiz, p. 205, 1865. 

 Cotteau. Echin. Foss. de l'Yonne, t. ii, p. 244, pis. lxviii, 



lxix, 1866. 

 Renevier. Notice sur les Alpes vaud., p. 171, 1867. 

 Bucaille. Foss. Cenomaniens de Rouen, p. 6, 1867. 

 Jaccard. Descr. Gcol. du Jura vaud. et Neuclmt., p. 120 



1869. 

 Greppin. Descr. Geol. du Jura Vernois, p. 143, 1870. 

 De Loriol. Echinologie Helvetique, p. 330, pi. xxvi, 



figs. 11—14, 1873. 



Diagnosis. — Test of a subglobular form, very nearly as broad and as high as it is 

 long. The upper surface regularly convex, sometimes a little elevated at the summit ; a 

 well-marked carina rises on the middle of the single inter-ambulacrum ; the under 

 surface more or less convex ; the ambitus rounded and inflated ; the ambulacra] summit 

 slightly excentral in the anterior direction ; posterior border narrow, obliquely truncated 

 downwards and inwards ; vent in the upper part of the area. 



Dimensions. — From a number of specimens collected by the Geological Survey from 

 different localities, the following table of comparative dimensions of six specimens, 

 selected on account of their differences, was prepared by my colleague the late Professor 

 Edward Forbes, to illustrate the variation in the proportions of this species. 



No. 

 1 



Locality. 



Stratum. 



Length. 



Breadth. 



Height. 



Dover 



Chalk-Marl 



9 4 



^i¥ 



2 5 - 



Z T2 



lit 



2 



Do. 



Lower Chalk 



2 



o 



ifV 



o 



Chaldon 



Chloritic Marl 



1 I i 



1 1 1 



l- 4 - 



1 12 



4 



Do. 



Do. 



1 12 



2 



1t 2 2 



5 



Do. 



Do. 



iA 



1& 



ItV 



6 



Do. 



Do. 



i* 



It 6 - 



h% 



Varieties, — There is a curious variety of this species, in which the anteal sulcus is 



