PLAGIOTHYRA. 
265 
1. Plagiothyba purpqra, cfArcliiac and de Verneuil, sp. PI. XXV, figs. 14, 14 a. 
1832. Ttjkbo nodosus, Goldfuss. In De la Beche's Handbook, Grerman edition, 
p. 533 (named only). 
1842. MoNODONTA PUEPUEEA, d' ArcTiiac and de Verneuil. G-eol. Trans., ser. 2, 
vol. vi, pt. 2, p. 358, pi. xxxii, fig. 15. 
1842. Turbo (Monodonta) granosus, 8andlerger. InNeues Jabrb. f. Min., 1842, 
p. 394, pi. viii B, fig. 8 a, h. 
1844. MoNODONTA PURPURA, Goldf. Petref. G-erm., vol. iii, p. 101, pi. cxcv, 
fig. 4. 
1848. Turbo geanosus, Bronn. Handbuch, vol. iii, p. 1320. 
1849. Trochus purpura, d'Orhigny. Prodrome, p. 64. 
1853. LiTTOEiNA PURPURA, Sandherger. Verst. Rbein. Nassau, p. 221, pi. xxv, 
figs. 17—19. 
1866. MoNODONTA PURPURA, Giebel. Eepertoriura, p. 105. 
1889. LiTTORiNA PURPURA, WJiidhome. Geol. Mag., dec. 3, vol. vi, p. 30. 
Description. — Shell small, turbiniform, of few volutions. Spire small, of broad, 
rapidly increasing whorls. Suture deep, rather wide, facing horizontally. 
Whorls moderately convex, bending in rather suddenly at the suture. Ornament 
consisting of seven or more rows of elevated, rounded, spiral ridges, separated by 
slightly wider furrows, and divided into nodules by perpendicular lines crossing 
the whorls almost in a straight line from the suture. Mouth unseen in the 
English specimens. 
Size. — Height about 10 mm., width about 11 mm. 
Locality. — There are four specimens in the Battersby Collection, which appear 
to have come from Lummaton or Barton. 
Remarks. — This is evidently a very beautiful and well-defined species. It has 
been well figured by d'Archiac and de Verneuil, by Goldfuss and by Sandberger, 
and their figures evidently agree, although the former authors represent the shell 
as a little more angulated or trochiform than do the latter. Sandberger,^ however, 
figures as varieties two far more angulated and depressed shells than that of 
d'Archiac, so that his shell evidently includes d'Archiac's. They all give the 
mouth, which is rounded, has the umbilicus closed by a callosity, and bears a large 
blunt central or subcentral tooth on the inner lip. The columella is merged into 
the lips on both sides. 
The English specimens in the Battersby Collection are all very defective, and 
would enable us to know very little about the species were it not that they evi- 
dently correspond with the German examples. They agree rather with Sandberger' s 
than with d'Archiac's figure. The cancellation of the surface is, however, very 
clearly shown in them. 
1 1853, Sandberger. ' Verst. Eliein. Nassau,' p. 222, pi. xxv, figs. 18, 19. 
