PULMONATA. 139 



of the characters distinguishing this new species ; but it is not improbable that Dr. Bey- 

 rich may have associated specimens of M. contabulata with the true M. hordeola. 



It is always hazardous, without the assistance to be derived from actual specimens* 

 to express an opinion on questions of identity; but the figure given by Dr. Beyrich 

 does not convey to my mind an idea of M. eburnea; the spire seems to be shorter 

 and thicker, the apex to be more obtuse ; the aperture to be shorter, less wide in front, 

 less narrow behind ; the outer lip is represented without the posterior sinus, and the 

 folds on the columella appear to be more oblique. The figure agrees much better with 

 M. contabulata, to which species, if it had been published, the German shell would 

 more probably have been referred. 



The present species appears to be confined to the older tertiary formations ; 

 the shells from Dax, and the neighbourhood of Bourdeaux, referred to it by Grateloup, 

 belong to a different species, which D'Orbigny has named M. sub-eburnea; as do those 

 from Turin, described by Sismonda, and to which Michelotti has given the name, 

 M. Taurinensis. 



Size, of the specimen figured, which forms part of Mr. D'Urban's collection, is, 

 axis, 3-10ths of an inch; diameter, half the length of the axis. The French speci- 

 mens are frequently much larger. 



Localities. — Bracklesham Bay, where it is very rare. French •. Grignon, Parnes, 

 Courtagnon, Ermenonville, Acy, le Tombray (fide D'Orb.). Italian ; Ronca, Val 

 Sangonini (fide Brogn.) German : Osterweddingen in Magdeburg ? (fide Beyr.) 



No. 81. Marginella bifido-plicata. Charlesworth. Tab. XVIII, figs. 2 a — g. 



M. testa minima, ovato-globosd, ad basin vix emarginatd; spird conicd, brevi, apice sub- 

 obtuso ; anfractibus convexis : aperturd angustd, longitudine spiram paulo super anti ; labro 

 crassissimo, compresso, extus marginato, inhis acuto, postice profunde emarginato ; columella 

 quadriplicatd, plicis trdbus posticis bifidis, pene transversis ; plied anteriori acuta, obliqud. 



Shell very small, roundedly ovate, with a short, conical spire and a bluntish apex : 

 aperture narrow, a little longer than the spire, with the margins nearly parallel : outer 

 lip much thickened, presenting a prominent border along the outer margin, a sharp 

 edge inwards, and a deep sinus near the suture ; columella with four folds, of which 

 the anterior one is sharp and very oblique, and the remaining three thick, bifid, and 

 nearly transverse. 



This marginella approaches very closely to a species from the Paris Basin, not yet 

 described, but to which M. Deshayes has given the name M. columbellina, and a com- 

 parison with a longer series of that species than I possess, may eventually establish the 

 identity. It appears, however, to be a broader and more ventricose shell, having a 



