116 CRETACEOUS LAMELLIBRANCHIA. 
Family—S PONDYLIDA, Gray. 
Grenus—Sponpyius, Linnewus, 1758. 
(‘Syst. Nat.,’ ed. 10, p. 690.) 
SronpyLus Rormeri, Deshayes, 1842. Plate XX, figs. 4 a—d. 
1841. Sponpynus Rapratus, Ff. A. Rimer (non Goldfuss). Die Verstein. d. nord- 
deutsch. Kreidegeb., p. 60. 
1842. — Latus, G. P. Deshayes (non Sowerby), in A. Leymerie. Mém. 
Soe. géol. de France, vol. v, 
pp. 10, 27, pl. vi, fig. 7. 
— — Roemert, Deshayes. Ibid., pp. 10, 27, pl. vi, figs. 8—10. 
1847, _ — A. @Orbigny. Pal. Franc. Terr. Crét., vol. ii, p. 655, 
pl. ecccli, figs. 1—6. 
1850. _ — @Orbigny. Prodr. de Pal., vol. ii, p. 83. 
1855. _ —  G. Cotteau. Moll. Foss. de ?Yonne, p. 118. 
1861. — —  P. de Loriol. Anim. Invert. Foss. du Mt. Saléve, 
p. 107, pl. xiv, figs. 4, 5. 
1870. _ — F.J. Pictet and G. Campiche. Foss. Terr. Crét. Ste. 
Croix (Matcr. Pal. Suisse, ser. 5), pp. 256, 260. 
2 187i: _- — W. A. Ooster.  Pteropodenschicht Schweizer-Alpen 
(Protozoe Helvetica, 2), pp. 126, 
141, pl. xvii, figs. 8—10. 
1883. — — W. Keeping. Foss., etc., Neoc. Upware and Brickhill, 
p- 113. 
1896. — — A. Wollemann. Zeitschr. d. deutsch. geol. Gesellsch., 
vol. xlvili, p. 834. 
1900. = —  Wollemann. Die Biv. u. Gastrop. d. deutsch. u. 
holland. Neoc. (Abhandl. d. k. preuss. 
geo). Land., n. F., pt. 31), p. 20. 
Description.—Shell oval in outline, the proportion of length to height variable, 
more or less oblique. Right valve flattened, with numerous radial ribs, usually 
faintly marked, and strong concentric lamellze. Left valve convex, with numerous 
slightly unequal ribs, separated by grooves of the same width; the larger ribs 
occur at regular intervals, and bear spines mostly directed ventrally : between 
the larger ribs are two or three smaller ribs, either smooth or with small spies. 
Ears of both valves apparently smooth. 
