PLEUROTOMARIA. 425 
where the basal rim is wanting or only slightly developed. ‘lhe body-whorl is 
bicarinate, though generally the keel which carries the sinus-band is the more 
prominent, the intervening space being much excavated. The periphery is more 
or less angular; base subconvex in the smaller specimens, very tumid in the larger 
ones, and apparently smooth. Aperture subquadrate, with inner lip but slightly 
oblique. 
Relations and Distribution—This species attains a considerable size, and its 
megalomorphs (P/. scalaris) present much variety. The smaller forms have some 
resemblance to Pl. reticulata, but may be distinguished by the smooth and rounded 
sinus-band, and also by the more angular shape of the whorls. 
The specimens in my collection are from the Pariinsoni-zone of Dorset. Fig. 8 
represents a bicarinate specimen of medium size (Pl. textilis) from P. 1, Burton 
Bradstock. From Halfway House are two large specimens, one of which (fig. 9) 
may be identified as Pl. scalaris, var. stricta, and another and still larger one (not 
figured) as Pl. scalaris, var. ambigua. 
Tawney mentions one specimen of Pl. textilis from Dundry, but this perhaps 
is a doubtful identification, 
366. PLevROTOMARIA PavorstTRIATA, d’ Orbigny, 1850. Plate XXXVII, fig. 1. 
1850. PxiervroroMaRria pavcrsrRiata, @’Orbigny. Prod., i, p. 269. 
1854. -—- — — Terr. Jur., vol. ii, p. 454, 
pl. ecelxxi. 
Syn. — PROTEUS, var. PAUCISTRIATA, Deslongchamps. Vol. cit., p. 
48, pl.i, fig. 2. 
Bibliography, §c.—This is simply a wide-angled member of the great Proteus- 
group, of which such large specimens are figured in the ‘ Memoirs of the Linnean 
Society of Normandy.’ ‘I'he softened outline of the whorls and the paucity 
of the tuberculations in this ‘ species,” together with the general character of the 
ornamentation, seems to connect the Ornate with the Fasciate. 
Description : 
Height (medium size) . ; : . 35 mm. 
Basal diameter : 3 : . 60 mm. 
Spiral angle. ; : 7 ten 
Shell conical, turrited, umbilicated. Spire regular. Whorls (eight or nine) 
angular and increasing by steps, the keel being situated in the posterior third of 
the whorl. The upper whorls have reticulate ornament, with nodules on the keel ; 
later on the nodules become fainter and gradually disappear, leaving a somewhat 
naked carina; the spiral ornament is continuous throughout. 
