PLEUROTOMARIA. 
281 
1866. Pleueotomaeia Lonsdalii, Oieiel. Eepertorium, p. 99. 
1889. — — Whidborne. aeol. Mag., dec. 3, vol. vi, p. 30. 
Description. — Shell rather small, flatly conical, of four or five rapidly increas- 
ing volutions. Spire of the form of a low convex cone. Suture deep, small, 
rectangular. Whorls narrow, curving immediately at the suture, then sloping 
obliquely and flatly to the lowest and widest part, and there curving rapidly 
inwards to form a broad, flat, and almost horizontal base. Umbilicus rather large, 
shallow. Mouth unseen. Surface above the sinus-band covered by about nine 
small, low, close, crenulated, spiral stride. Sinus-band apparently convex and 
slightly truncating the curve at the widest or supersutural part, but very 
indistinctly seen. 
Size. — Height 13 mm., width 18 mm. 
Locality. — Wolborough, A single specimen is in the Museum of Practical 
Geology. 
Remarhs. — The only specimen I have seen is in a very poor state of preserva- 
tion, and its ornamentation can only be approximately traced. As far as can be 
judged it appears to be referable to the shell described by d'Archiac and de 
Verneuil, although its spiral strise seem to have been considerably more 
numerous. These authors state the spiral striae on the back of the whorls to 
have been only four, with, however, some smaller intermediate ridges. In their 
figure, however, as well as in that given by Gloldfuss, about six are shown, while 
in Fl. euryomphalus, which Sandberger himself identifies with PI. Lonsdalii, nine 
are drawn, and they are described as " numerous." As our specimen is rather 
larger than d'Archiac and de Verneuil's figure it is possible that this may in 
part account for the difi'erence. On the whole there seems no reason to doubt 
its identity. 
Affinities. — PI. Beaumontii d'Archiac and de YerneuiP has a higher spire, 
more convex whorls and a more distinct cancellation. 
Trochus Klippsteinii Goldfuss^ is not very dissimilar from it in general shape, 
but is a much flatter shell, with more evenly convex whorls and a more rounded 
base. Its ornamentation appears difierent. 
In PI. fragilis de Koninck^ from the Carboniferous, which is very closely 
allied, the ornament seems more distant, the spire less conical, and the whorls 
more evenly convex. 
^ 1842, d'Archiac and de Verneuil, ' Greol. Trans.,' ser. 2, vol. vi, pt, 2, p. 361, pi. xxxiii, figs. 1, 1 a. 
2 1844^ Groldfuaa, 'Petref. Germ.,' vol. iii, p. 50, pi. clxxxi, fig. 1. 
3 1842-4, de Koninck, ' Desc. Anim. Foss.,' p. 372, pi. xxxv, figs. 8 a — c. 
