120 CRETACEOUS LAMELLIBRANCHIA. 
? 1868. Sponpytus striatus, H. Hichwald. Lethza Rossica, vol. ii, p. 422. 
1870. — — F. J. Pictet and G. Campiche. Foss. Terr. Crét. Ste. 
Croix (Mater. Pal. Suisse, ser. 5), p. 261. 
1872. — — A. B. Geinitz. Das Elbthalgeb. in Sachsen (Palie- 
ontographica, vol. xx), pt. 1, 
p. 186, pl. xlu, figs. 1—3. 
P 1877. — — A, Fritsch. Stud. im Gebiete der bohm. Kreidef. : IT, 
Die Weissenberg. u. Malnitz. Schicht., p. 138. 
1878. — -- G. Behrens. Zeitschr. d. deutsch. geol. Gesellsch., 
vol. xxx, p. 259. 
1893. — —- R. Michael. Ibid., vol. xlv, p. 237. 
1895. — — E. Tiessen. Ibid., vol. xlvii, p. 475. 
1897. — -- R. Leonhard. Die Kreidef. in Oberschles. (Palaon- 
tographica, vol. xliv), p. 50. 
Non 1822. Popopsis striata, A. Brongniart. Descript. géol. des Envir. de Paris. In 
Cuvier, Ossem. foss., ed. 2, vol. ii, 
pp. 319, 604, pl. v, fig. 3. 
— 1870. Sponpyxus striatus, F. Romer. Geol. von. Oberschles., p. 315, pl. xxxvii, 
figs. 3, 4. 
Descrviption.—Shell large, obliquely ovate, high; anterior and ventral margins 
regularly rounded; posterior margin slightly concave or nearly straight. 
Right valve usually more inflated than the left, and generally attached by the 
larger part of its surface ; free part with radial ribs, separated by shallow grooves, 
and crossed by numerous very fine concentric lamelle. 
Left valve moderately convex, umbonal part prominent and produced; surface 
sometimes undulating; ribs numerous, equal, smooth, flattened, separated by deep 
grooves except on the later formed parts of the valve, where the grooves become 
shallow and the ribs less distinct. The grooves and ribs are crossed by concentric 
lamellee, like those on the right valve. Ears smooth except for growth-lines. 
Measurements of left valve : 
(1) (2) (3) (4) 
Length F : . : 56 52 50 4.0 min. 
Height : ; ' ; WY 65 ~ 58 AS ,, 
(1—4) from Warminster. 
Affinities.—For the relation of this species to 8. latus, Sowerby, see p. 123. 
S. hystrix, @Orbigny (? Goldfuss) is distinguished from this species by the left 
valve being less convex, the umbo less produced, the narrower and more widely 
separated ribs, and the spines on the earlier part of the valve. 
S. capillatus, @’Archiac, from the Tourtia of Tournay, has been regarded by 
Geinitz, d’Orbigny, and other authors as a synonym of XW, striatus ; specimens 
