424 GASTEROPODA OF THE INFERIOR OOLITE. 



wrinkles on the posterior areas are, also, strongly developed, — a feature which is 

 emphasised in d'Orbigny's figures, but is probably of no great importance. Morris 

 (' Quart. Journ. Geol. Soc.,' vol. ix, p. 326) quotes PL reticulata, Desl., with a 

 query, from the Ponton beds. 



365. Pledeotomaeia textilis, Deslong champs, 1848. Plate XXXVI, fig. 8 ; 



including PL scalaris, Deslongch., fig. 9. 



1848. Pleurotomaria textilis, Deslongchamps. Vol. cit., p. 63, pi. ix, fig. 2. 

 1850. — D'Orbigny, Prod., i, p. 268. 



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



p. 492, pi. cccxci, figs. 6 — 10. 

 1873. — — — Tawney, Dundry Gasteropoda, 



p. 53. (45). 

 Syn. or var. — scalaris, Deslongchamps. Vol. cit., p. 66, pi. vii, fig. 4 ; 



pi. viii, figs. 1, 2, 3 ; pi. ix, 



fig. 1. 



Bibliography, 8fc. — Not without hesitation Deslongchamps concluded to 

 separate PL textilis and PL scalaris, though doubting the validity of the latter 

 species. Finally he left it an open question. D'Orbigny recognised three species 

 in this group, viz. PL textilis, Deslongch. (' Terr. Jur.,' vol. ii, p. 492, pi. cccxci) ; 

 PL strigosa, d'Orb. (vol. cit., p. 504. pi. cccxcvi) ; and PL subscalaris, d'Orb. (vol. 

 cit., p. 505, pi. cccxcvii). 



For the present I am content to regard the scalaris section of this group as 

 representing megalomorphic forms of PL textilis, which must be accepted as the 

 specific name. 



Description (medium size = PL textilis) : 



Height . . . . .60 mm. 



Basal diameter . . . .48 mm. 



Spiral angle ..... 56°. 



Shell conical, turrited, not umbilicated. Spire regular. Whorls (about nine) 

 angular and bicarinate or subbicarinate, according to the greater or less 

 prominence of the basal rim. The whorls increase by steps, and in some cases 

 are rather undercut ; sutures close. In well-preserved specimens the ornaments 

 of the apical whorls are seen to be reticulate, but in the later whorls spiral 

 ornamentation alone prevails. 



The sinus-band is nearly median, large, round, and prominent ; and apparently 

 without ornament other than curved growth-lines ; it is situate at the angle, and 

 constitutes the greatest salience of each whorl, being more especially conspicuous 



