PLEUROTOxMARIA. 
283 
Affinities. — It comes very near PL Beaiimonti, d'Arch. and de VerneuiP in 
general shape, but differs from it in its much greater size, its more convex spire, 
and the closeness of its ridges. Goldfuss's figure of that species^ also shows that 
the sinus-band was of different character, being a simple concave band marked by 
fine arching strige. Sandberger identifies PI. Beaumonti with his PI. decussata 
var. elegans,^ which differs from the present shell in the same particulars, and is 
clearly distinct. 
PI. elegans, d'Arch. and de Verneuil,* more nearly approaches it in ornament, 
but is much more elevated, and appears to belong to a distinct group of sinistral 
shells. 
PI. gemmulifera, Phillips,^ as given by de Koninck/ is less turrited, and has 
broader furrows, minute and definite granules, and a better defined sinus-band. 
PI. granulata, de Koninck,''' is also rather similar, but is considerably more 
elevated, and has a convex granulated sinus-band. 
PI. Hebe, Hall, appears so close to the present shell that neither from Hall's 
figures nor rather short description can I see any sufficient reason for separating it. 
Neither the English nor the American specimens are very well preserved, and it is 
possible that with better specimens points of specific divergency might be brought 
to light. At present the only striking point in the American form is the great 
angularity of the body-whorl at the sinus-band, but this character vanishes in 
some of his specimens. 
5. PLBUB0T0MA.EIA Orbigniana, D' ArcMac and de Verneuil. PI. XXYII, fig. 14. 
1842. Plettrotomaeia Oebigntana, d^Archiac and de Verneuil. Geol. Trans., 
ser. 2, vol. vi, pt. 2, p. 359, pi. xxxii, 
figs. 18—20. 
? 1842. — Beaumonti. Ibid., p. 361, pi. xxxiii, fig. 1, 1 a. 
184)2. — ■ Oebigntana, d'Archiac and de Verneuil. Bull. Soc. 
Geol. Fr., vol. xiii, p. 261. 
1842. — ■ BECTTSSATA, Sandlerger. In Neues Jahrbuch f. Min., 
p. 392, pi. viiiB, figs. 60 — c. 
1 1842, d'Archiac and de Verneuil, ' Geol. Trans.,' ser. 2, vol. vi, pt. 2, p. 361, pi. xxxiii, figs. 1, 1 a. 
^ 1848, Goldfuss, ' Petref, Germ.,' vol. iii, p. 62, pi. clxxxii, fig. 8. 
^ 1853, Sandberger, ' Verst. Ehein. Nassau,' p. 197, pi. xxiv, figs. 3, 3 a — d. 
* 1842, d'Archiac and de Verneuil, ' Geol. Trans.,' ser. 2, vol. vi, pt. 2, p. 360, pi. xxxiii, figs. 3, 
3 a — c. 
^ 1836, Phillips, ' Geol. Yorks.,' pt. 2, p. 227, pi. xv, fig. 19. 
^ 1842-4, de Koninck, ' Desc. Anim. Foss.,' p. 370, pi. xxxi, figs. 7 a—d. 
7 Ibid., p. 373, pi. xxxiii, figs. 3 a — c. 
37 
