PLEUROTOMARIA. 305 
Pleurotomaria arata, Hall/ has a higher spire, a broader sinus-band, strong 
transverse ridges, and a more angulated section. 
Euomphalus nanus, Eichwald,^ has a much more depressed spire, and a 
decidedly deeper suture. 
19. Pleurotomaria Bischofpii, Goldfuss. PL XXXI, figs. 1, 1 a. 
1844i. PiEUBOTOMAEiA BiscHOFPii, Goldfuss. Petref. Germ., vol. iii, p. 65, pi. 
clxxxiii, fig. 4. 
1853. — CALCULiPOEMis, SaTidberffer. Verst. Ehein. Nassau, p. 193, 
pi. xxii, fig. 14. 
1889. — — WUdborne. Geol. Mag., dec. 3, vol, vi, p. 30. 
Description. — Shell very small, lenticular, depressed, globose or turbinate. 
Spire conical, very low, of five whorls. Suture very slightly marked. Whorls 
almost flat close to the suture, and then curving with a nearly semicircular 
curvature to form the sides of the shell. Upper whorls very much enveloped by 
those below. Surface smooth except that there are signs of a raised rounded 
sinus-band or keel, which is distant about half the width of the whorl from the 
suture. Shell-structure thick. Mouth and umbilicus hidden. 
Size. — Height, 6 mm. ; width, 10 mm. 
Locality. — Lummaton. There is a specimen in the Woodwardian Museum, 
which was collected by Mr. B. B. Tawney from that place. 
Remarks. — Except that there are signs of very minute spiral strias, Sand- 
berger's species corresponds exactly with our specimen. It agrees both in general 
shape and in the postion and convexity of the sinus-band. Its aperture is 
possibly slightly larger, but there can, I think, be no doubt of its identity. The 
sinus-band in the English specimen is very indistinct, and but for the exact corre- 
spondence with Sandberger's species might well be overlooked, but a close exa- 
mination leaves, I think, no doubt that it really exists. 
Sandberger identifies his species with Pleurotomaria Bischoffi-i, Goldfuss^ which 
he describes as only a cast, though Goldfuss does not mention this. Goldfuss's 
figure is quite smooth and has perhaps more quickly increasing whorls and a wider 
sinus-band than the English shell. As no side view is given the elevation of 
the shell cannot be compared ; but there is no cause for questioning the correct- 
1 1879, Hall, ' Pal. N. T.,' vol. v, pt. 2, p. 64, pi. xvii, figs. 1—10. 
2 1857, Eichwald, 'Bull. Soc. Nat. Moscow,' p. 150; and 1860, 'Lethaea Eossica,' p. 1635, pi. Ix, 
figs. 26 a — c. 
^ 1844, Goldfuss, ' Petref. Germ.,' vol. iii, p. 65, pi. clxxxiii, figs. 4 a, h. 
