SPONDYLUS. 117 



Measurements .- 



Length . . . 38 nun. 



. Height -to „ 



Thickness 2:3 „ 



Affinities. — This species appears to be closely allied to ;S\ gibhosus, d'Orbigny, 

 hut the ribs are more spiny and rather coarser, and the valves less convex in pro- 

 portion to their size. It seems to differ from 8. striato-rostatns, d'Orbigny, in 

 having more numerous and more slender ribs. 



llemarks. — Deshayes' figures 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 8. 

 Koemevi. 



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 Foucheres, in the Ecole des Mines, Paris. 



Distribution. — Perna-hedi of Atherfield. Lower Greensand of Brickhill.^ 



Spondylus gibbosus, 'VOrtn'gny, 1847. Plate XX, figs. 5, 6 a — r, 7 a — c,H a, l>, 



S) a, I), 10, 11. 



1847. Spondylus gibbosus, A. d'Orbigny. Pal. Franc,'. Terr. Cret., vol. iii, 



p. 658, pi. cccclii, figs. 1 — 6. 

 1850. — — d'Orbigny. Prodr. de Pal., vol. ii, p. 139. 



1853. — Brunneei, F. J. Pidet and W. Roux. Moll. Foss. Gres verts 



de Greneve, p. 514, pi. xlvii, fig. 1 (? 2). 

 1858. — — F. J. Pidet and E. Benevier. Foss. Terr. Aptieu 



(Mate'r. Pal. Suisse, ser. 1), p. 136. 

 1866. — GIBBOSUS, H. G. Seeley. Ann. Mag. Nat. Hist., ser. 3, vol. xvii, 



p. 177. 



1870. — F. J. Pidet and G. Campiche. Foss. Terr. Crc't. Ste. 



Croix (Mater. Pal. Suisse, ser. 5), 

 p. 257, pi. clxxxii, figs. 1 — 4. 

 1875. — — A. J. Jukes-Browne. Quart. Jourii. Geol. Soc, 



vol. xxxi, p. 297. 

 — — DvTEMFi,EXJi!Vs? 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 Spondylan, 

 but I have not succeeded in finding the type or any otiier specimens. Sharpe, ' Quart. Journ. Geol. 

 Soc.,' vol. X (1853), p. 197, pi. vi, fig. 3. 



