290 
DEVONIAN FAUNA. 
wliorl. Murchisonia migulata, Phillips,^ is a miicli more elevated shell, while PL 
angulata, Sowerby,^ is totally distinct from both species. 
PI. Daleidensis, Romer,^ is very similar, and seems to agree in ornamen- 
tation, but it differs in being shorter and more cone-shaped, and in having a much 
narrower and less prominent sinus-band. 
PI. striata, Goldfuss,* also seems somewhat similarly ornamented, but is 
distinguished by being much flatter, with differently shaped whorls, more numerous 
spiral ridges, and a flatter and less prominent sinus-band. With this shell 
Sandberger identifies his PI. creiiatostria.taj' which differs from the present form 
in much the same particulars. He, however, figures, as an elevated variety, a very 
dissimilar shell, which comes very much nearer to it, and may possibly be 
identical. It has, however, less expanded and more slowly increasing whorls, its 
sinus-band seems higher up, its transverse ornamentation is much better shown, 
and its boundary ridges are hardly so prominent. 
PI. exaltata, d'Archiac and de Verneuil,^ is distinguished by its broad convex 
sinus-band. 
PI. trochoides differs in having well-defined ridges or keels on the upper part 
of the whorls. 
9. Pleueotomaeia aspeea, Sowerhy. 
1840. Pletjeotomabia aspeea, Sotoerhy. Geol. Trans., ser. 2, vol. v, ser. 3, pi. liv, 
fig. 16. 
1841. — — Phillips (pars). Pal. Foss., p. 96, pi. xxsvii, fig. 
177 c (only). 
1854. — — Morris. Catal. Brit. Foss., p. 272. 
Bemarhs. — Sowerby's original specimen from Plymouth is in the Woodwardian 
Museum, and is a beautiful and very distinct shell. Phillips quotes it from Pilton, 
South Petherwyn, and Newton, but his figures seem to include more than one 
species, the figure 177 c alone agreeing with Sowerby's type. In the ' Geol. Mag.' 
for 1889''^ I separated the shell represented by figs. 177 a and b under the name 
of PI. distinguenda. I then thought that two poor specimens from Wolborough in 
the Museum of Practical Geology belonged to that shell, but a further examination 
1 1841, Phillips, ' Pal. Foss.,' p. 101, pi. xxxix, fig. 189. 
2 1839, Sowerby, in Murchison's ' Sil. Syst.,' p. 641, pi. xxi, fig. 20. 
^ 1844, F. A. Romer, ' Rhein. Uebergangsgeb.,' p. 80, pi. ii, figs. 7 a, h. 
* 1844, G-oldfuss, ' Petref. Germ.,' vol. iii, p. 61, pi. clxxxii, fig. 4. 
^ 1853, Sandberger, ' Verst. Rhein. Nassau,' p. 188, pi. xxiii, figs. 2, 2 a— d. 
^ 1842, d'Archiac and de Verneuil, ' G-eol. Trans.,' ser. 2, vol. vi, pt. 2, p. 361, pi. xxxiii, fig. 5. 
7 1889, ' Geol. Mag.,' dec. 3, vol. vi, p. 30. 
