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 PI. 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 Ornatae and the Granulata? may, 

 to a certain extent, approach each other in these two species. 



Practically, then, as a member of the Granulatse, PL Yeovilensis stands alone 

 in the Co?icavus-be& 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 PI Alcibiades. 



381. PleurotOiMaria granulata, Sowerby, 1818. Plate XXXIX, figs. 10 a, 10 b, 



10 c; and Plate XL, figs. 1, 1 a. 

 1818. Teochus geanulatus, Sowerby. Min. Conch., pi. ccxx, fig. 2. 

 1873. Pleueotomaeia gbanulata, Sowerby. Tawney, Dundry Gasteropoda, 



p. 47 (39). 

 Syn. — vara, eeticulata and ccelata, Deslong- 



champs. Vol. cit., p. 101, pi. xvi, figs. 6 

 and 8. 



Bibliography, 8fc. — 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 granalatus, Sow., may be accepted as the central figures of 

 the Granulata-gr oup, the others being regarded as species or varieties according to 

 individual opinion. 



