440 GASTEROPODA OF THE INFERIOR OOLITE. 
marginal furrow, from which it rises towards the edge of the umbilicus: through- 
out the base spiral lines are decussated by bold sinuous radii, which die out before 
reaching the marginal furrow. The umbilicus is steep and smooth, and so deep 
as to expose the internal coils. Aperture oval, depressed. 
Var. rugosior.—Of somewhat larger habit than the preceding. The spiral 
angle is scarcely 90°; consequently the sides of the shell are steeper, whilst the 
ornaments are coarser, especially throughout the base; the umbilicus, too, is 
narrower, but equally steep and penetrating. 
Relations and Distribution.—Although Pl. Yeovilensis possesses considerable 
general resemblance to Pl. Baugieri, especially in its basal aspect, the very 
different character of the sinus-band forbids them being placed even in the same 
section. It is not impossible, however, that the Ornatz and the Granulate may, 
to a certain extent, approach each other in these two species. 
Practically, then, as a member of the Granulate, Pl. Yeovilensis stands alone 
in the Concavus-bed of Bradford Abbas, where excellent specimens are by no 
means rare. If we desire to see the change wrought through lapse of time we 
have a remarkable instance in the var. rugosior, which represents this species on 
the next horizon, viz. the Sauzei-bed of Oborne. Specimens from Beaminster 
and Dundry are rare, and not very satisfactory. There is one specimen in my 
Collection from Bradford Abbas, which in its depressed spire and soft ornamenta- 
tion might almost pass for Pl. Alcibiades. 
381. PrevRoTomARIA GRANULATA, Sowerby, 1818. Plate XX XIX, figs. 10 a, 106, 
10c; and Plate XL, figs. 1, 1a. 
1818. Trocuus eranuLatus, Sowerby. Min. Conch., pl. cexx, fig. 2. 
1873. PLevRoromarIA @RanuLata, Sowerby. Tawney, Dundry Gasteropoda, 
p- 47 (39). 
Syn. — — vars. RETICULATA and ca@Lata, Deslong- 
champs. Vol. cit., p. 101, pl. xvi, figs. 6 
and 8. 
Bibliography, Se.—Morris (‘ Cat.,’ p. 271) quotes Pl. granulata, Sowerby, from 
the Corallian of Malton and Scarborough ; and also from the Inferior Oolite of 
Blue Wick (Dogger). There is no justification for this. He also quotes the 
species from Dundry, which is correct. 
The forms described below, which I regard as being nearly if not absolutely 
identical with Trochus granulatus, Sow., may be accepted as the central figures of 
the Granulata-group, the others being regarded as species or varieties according to 
individual opinion. 
