SPONDYLUS. 117 
Measurements : 
Length . : : : : : Poo anim: 
Height. , F : : ; : : 1 a0 a 
Thickness . 5 : : : : : h LeD 95 
Affinities. —This species appears to be closely allied to S. gibbosus, VOrbigny, 
but the ribs are more spiny and rather coarser, and the valves less convex in pro- 
portion to their size. It seems to differ from S. striato-costatus, d’Orbigny, in 
having more numerous and more slender ribs. 
Liemarks.—Deshayes’ ficures of this species appear to represent worn specimens, 
and consequently do not show the real characters of the ornamentation. In the 
absence of other specimens from the locality of the types one is obliged to rely on 
the figures and descriptions by d’Orbigny as giving the specific characters of S. 
Roemer. 
This species appears to be very rare in England. The examples from Brickhill 
are rather water-worn, but the stumps of the spines remain on some of the ribs. 
Types.—From the Neocomian of Fouchéres, in the Ecole des Mines, Paris. 
Distribution —Perna-bed of Atherfield. Lower Greensand of Brickhill.’ 
SponpyLus Gipposus, d’Orbigny, 1847. Plate XX, figs. 5, 6 a—e, 7 a—e,8 u, b, 
9 a, b, 10, 11. 
1847. Sponpyius eipposus, A. d’Orbigny. Pal. France. Terr. Crét., vol. i, 
p. 658, pl. ceeclii, figs. 1—6. 
1850. — = @ Orbigny. Prodr. de Pal., vol. 11, p. 189. 
1853. _- Brunnert, F. J. Pictet and W. Roux. Moll. Foss. Gres verts 
de Genéve, p. 514, pl. xlvii, fig. 1 (? 2). 
1858. — — F. J. Pictet and E. Renevier. Foss. Terr. Aptien 
(Matcér, Pal. Suisse, ser. 1), p. 156. 
1866, — arpposus, H. G. Seeley. Ann, Mag. Nat, Hist., ser. 3, vol. xvii, 
ined WAC 
1870. -- — F. J. Pictet and G. Campiche. Foss. Terr. Crét. Ste. 
Croix (Matér. Pal. Suisse, ser. 5), 
p. 257, pl. elxxxii, figs, 1—4. 
1875. -- — A, J. Jukes-Browne. Quart, Journ. Geol. Soc., 
vol. xxxi, p. 297. 
— - DuremMPLEANUS? Jukes-Browne. Ibid., p. 297. 
— — = J. Phillips. Geol. Yorks., ed. 3, pt. 1, p. 245. 
1 Dianchora ? guttata, Sharpe, from the Lower Greensand of Faringdon, is probably a Spondylus, 
but I have not succeeded in finding the type or any other specimens. Sharpe, ‘ Quart. Journ. Geol. 
Soc.,’ vol. x (1853), p. 197, pl. vi, fig. 3. 
