SPONDYLUS. 125 
d’Orbigny,' differs from this species in having stronger ribs at regular intervals, 
and in being proportionately higher. 
S. asper, Goldfuss,’ is similar in form, but the spines are coarser, fewer, and 
less regular. 
S. occultus, Geinitz,* is a very small (7 mm.) form, which may be closely related 
to S. serratus, but the ribs appear to be more unequal and to bear tubercles which 
are in contact, instead of spiny processes distinctly separated from one another. 
Remarks.—This is a very rare species; I have seen only five examples which 
could be definitely referred to it. 
Distribution.—Marsupites-zone (Uintacrinus-bed) of Devizes Road, near Salis- 
bury, and the Thanet coast. 
SponpyLus DurempLeanus, @’ Orbigny, 1847. Plate XXII, figs. 11a, b, 12a, b, 13, 
14; Plate XXIII, figs. 1—5. 
1833. Drancnora sprnosa, S. Woodward. Geol. Norfolk, p. 48, pl. vy, fig. 24. 
1847. Sponpytus Durempreanus, A. d’Orbigny. Pal. France. Terr. Crét., vol. iii, 
p- 672, pl. eccelx, figs. 6—11. 
1850. — — — Prodr. de Pal., vol. ii, p. 254. 
1869. — _ Hi. Favre. Moll. Foss. de la Craie de Lemberg, 
p. 159, pl. xiii, figs. 14, 15. 
1870. - - F. J. Pictet and G. Campiche. Foss. Terr. 
Crét. Ste. Croix (Matér. Pal. Suisse, 
ser. 5), p. 262. 
1887. -- Durempe!, A. Peron. Hist. du Terr. de Craie (Bull. Soc. 
Sci. hist. et nat. de ’Yonne, ser. 3, 
vol. xii), p. 166. 
1889. —- Durempueanus, FE. Holzapfel. Die Mollusk. d. Aachen. 
Kreide. (Paleontographica, vol. xxxv), 
p. 244, pl. xxvii, figs. 8—10. 
1891. — — J. Bohm. Die Kreidebild. des Firbergs, 
etc. (Paleontographica, vol. xxxviii), p. 88. 
1892. — — EB. Stolley. Die Kreide Schleswig-Holsteins 
(Mitth. a. d. Min. Inst. Kiel, vol. i), p. 236. 
Non 1875. os a= ?, A. J. Jukes-Browne. Quart. Journ. Geol. 
Soc., vol. xxxi, p. 297. 
Description.—Shell oval, shghtly oblique, usually inflated, rounded ventrally, 
pointed and produced in the umbonal region. Right valve sometimes with greater, 
1 «Pal. Franc. Terr. Crét.,’ vol. iii (1847), p. 671, pl. cecclx, figs. 1—5. 
2 * Petref. Germ.,’ vol. ii (1836), p. 96, pl. evi, fig. 1. 
3 “Das Elbthalgeb. in Sachsen” (‘ Paleeontographica,’ vol. xx, pt. 1), p. 207, pl. xlvi, fig. 1. 
(N.B.—Enlarged about three times.) 
