154 PELTASTES 



tion of the Gault and the base of the Upper Greeiisand ; this stratum, about nine feet 

 thick, contained small GryphtecB and TcrebratuJa semit^lobosm with the Peltasfes ; and 

 few fossils besides these. The apical disc (fig. 1 b) shows many punctuations in the line 

 of the sutures ; one entire ambulacraj magnified four times, is shown (fig. 1 /), and 

 one entire inter-ambulacra, equally enlarged, in fig. \ e ; the structure of a single plate, 

 magnified six times, in fig. 2 y, and the disc isolated, magnified foiu* diameters, is shown 

 in fig. 1 d. All these figures are drawn with the utmost care and truthfulness for 

 comparison with other varieties of this species collected from the Sponge-Gravel of 

 Farringdon and figured in PI. XXXI, figs. 1 — 3. For an account of the Red Chalk of 

 Speeton, in which this Peltastes was collected, the reader is referred to page 8 of this 

 Monograph. 



Affinities and Differences. — P. stellulatus resembles P. Wrightii, but, according to 

 M. Cotteau, the species are quite distinct. M. Cotteau had a large series of the different 

 varieties of P. stellulatus to compare with specimens of P. Wrightii from Farringdon, sent 

 him by my lamented colleague, Professor Edward Forbes, and after a careful study of 

 these fossils my learned friend observes, it is true, that P. stellulatus (var. punctata) 

 closely resembles P. Wrightii, but nevertheless it is separated from it by its form being 

 more inflated, its tubercles more numerous and less prominent, its apical disc more smooth, 

 less thick, and marked only with some isolated points.' 



Locality and Stratigraphical Position. — This species, which is very rare in England, 

 was collected from the Lower Greensand at Farringdon, Berks, and the Red Chalk at 

 Speeton, near Filey Bay, Yorkshire. 



It is abundant, according to M. Cotteau, in France, in the Neocomien inf. et moyen 

 at Saint-Sauveur, Fontenoy, Leugny, Auxerre, Bernonil, Tronchoy (Yonne) ; Marolles, 

 Soulaines (Aube) ; Saint-Dizier (Haute-Marne) ; Germigney (Haute-Saone) ; Fontanil 

 (Isere) ; Ceuseau, les Rousses (Jura), where it is abundant ; and in Switzerland, 

 according to Professor Desor, in the etage Valanginien or Neocomien inf. at La Chaux- 

 de-Fonds, Sainte-Croix, Hauterive, Lauderon pres Neuchatel. 



Peltastes Lardyi, Desor. PI. XXXI, fig. 4 a, b, c, d. 



Hyposalenia Lardyi, Desor. Synops. des Echinides Fossiles, p. 148, 1856. 

 Salenia acupicta, Desor. Ibid., p. 152. 



Hyposalenia Lakdyi, Pictet et Benevier. Foss. du terr. Aptien de la Perte du Rhone, 



p. 161, 1858. 

 Peltastes Lardyi, Cotteau. Paleontologie Fran9aise, terr. Cretace, t. vii, p. 106, 



pi. 1024, 1862. 



Test circular, upper surface convex, under surface flat, sides inflated, poriferous zones 

 straight, ambulacra narrow, straight, two rows of homogenous mammillated granules, 

 ' 'Paleontologie Fran^aise, terrain Cretace,' t. vii, p. 105. 



