426 GASTEROPODA OF THE INFERIOR OOLITE. 



The sinus-band is situated a little above the centre of the subcarinal portion of 

 the whorls ; it is wide, flat, and non-salient; a strong spiral line in the middle may 

 be noted, but later on this seems to undergo modification. The body-whorl is 

 bicarinate with a sharp angle at the periphery (more like d'Orbigny's figure than his 

 description). Generally, too, the basal angle is subnodular, almost like that in PL 

 subfasciata. Base flat, with a large umbilical excavation, the spiral striae being 

 faint and confined to the outer margin. Aperture oval and oblique. 



Relations and Distribution. — As a member of the Proteus-group its relations 

 have already been partially indicated. The figured specimen is from the Iron-shot 

 Oolite of Dundry. I have a large specimen from the Humphriesianus-zone of the 

 Sherborne district, and a few smaller oues. It is less abundant than the species 

 next described. 



367. Plkurotomaria Proteds, Deslong champs, 1848. Plate XXXVII, fig. 2. 



1848. Plettrotomaria Proteus, var excelsa, Deslong champs. Vol. cit., p. 50, 



pi. i, fig. 1. 

 1854. Deslongcliamps . D'Orbigny, Terr. Jur., vol. ii, 



p. 453, pi. ccclxx. 

 1873. — Tawney, Duudry Gasteropoda, 



p. 52 (44). 



N.B. — It should be borne in mind that specimens, such as the one figured, are 

 incomplete, and do not attain to the smooth stage, as is the case with the very much 

 larger ones in Normandy. 



The height of the largest British specimen known to me is about 50 mm. ; 

 whilst the spiral angle is at least 10° narrower than in PI. paucistriata ; the whorls 

 are drawn out axially and have a rather different shape, whilst the umbilicus is 

 very narrow. The nodules on the carinas are bolder and more wide apart in PI. 

 Proteus than in PI paucistriata, but there are intermediate forms. The elongate 

 specimens which I refer to PI. Proteus are most abundant in the Humphriesianus- 

 zone of Louse Hill ; and, generally speaking, the group is chiefly found in the 

 Sherborne district. 



From Louse Hill (upper part of Humphriesianus-zone) I have likewise a portion 

 of a large specimen indicative of PI. constricta, Deslongch. This species, as the 

 author remarks (vol. cit., p. 42), links the varieties of PI. Proteus with those of PL 

 armata. 



