PLEUROTOMARIA. 425 



where the basal rim is wanting or only slightly developed. The 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 (PL scalaris) present much variety. The smaller forms have some 

 resemblance to PI. 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 Parkinsoni-zone of Dorset. Fig. 8 

 represents a bicarinate specimen of medium size (PI. textilis) from P. 1, Burton 

 Bradstock. From Halfway House are two large specimens, one of which (fig. 9) 

 may be identified as PI. scalaris, var. strict a, and another and still larger one (not 

 figured) as PL scalaris, var. ambigua. 



Tawney mentions one specimen of PI. textilis from Dundry, but this perhaps 

 is a doubtful identification. 



366. Pleurotomaria pauoistriata, d'Orbigny, 1850. Plate XXXVII, fig. 1. 



1850. Pleurotomaria pauoistriata, d'Orbigny. Prod., i, p. 269. 



1854. — Terr. Jur., vol. ii, p. 454, 



pi. ccclxxi. 

 Syn. proteus, var. pauoistriata, Deslongchamps. Vol. cit., p. 



48, pi. i, fig. 2. 



Bibliography, Sfc. — 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.' The 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 Ornatas with the Fasciatse. 

 Description : 



Height (medium size) . . . .55 mm. 



Basal diameter . . . .60 mm. 



Spiral angle ..... 72°. 

 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. 



