160 EOCENE MOLLUSCA. 



pansis ; sulcis transversis distantibus, ad basin latis, profundis : aperturd postice sub-cana- 

 liculatd, antice late emarginatd ; labro tenui, simplici ; labio effuso, postice incrassato ; 

 columella arcuatd, quater vel quinquies plicatd. 



Var ? Plattspina, fig. 1 c. Testa tuberculis nodiformibus, crassis, lateraliter com- 

 pressis, cor on at a. 



Shell ovately oblong, contracted at the base, obscurely ribbed, transversely fur- 

 rowed, with a short, rather conical, and pointed spire : whorls angulated at the 

 shoulder, and crowned with a single row of large, wide-spreading spines. The bases 

 of the spines are prolonged into thick, obscure ribs, which do not extend beyond the 

 middle of the whorls. In the young state, the ribs are numerous, and surmounted by 

 two rows of small, sharp spines ; as the shell increases in size, the ribs become more 

 distant, and the row of spines nearest to the suture disappears, and is replaced by a 

 sharp, elevated ridge. The transverse furrows are distant, and broad and deep at 

 the base. The aperture is contracted in front, obscurely channelled close to the suture, 

 and widely, but not deeply, notched in front ; outer lip thin, sharp edged, and smooth 

 within ; inner lip widely spread, thickened posteriorly, and extending backwards as far 

 as the suture; columella flattened in front, curved, and furnished with four or five folds, 

 of which the one in front is the largest. In the last whorls, the sutural margin is 

 spread over the preceding whorl up to the spines, which, in some instances, are covered 

 by it. 



In the specimen represented by fig. 16, tab. 5, in Mr. Dixon's work, the outer lip 

 is broken off, and the shell consequently presents the turbinate form which charac- 

 terises V. spinosa (Lamk.) ; and this circumstance probably induced Mr. Sowerby to 

 refer it to that species ; from which, however, it is distinguished by the transverse 

 furrows, and the arched and flattened columella. 



In the specimen (fig. 1 c) for which the variety platyspina was proposed by Mr. 

 Sowerby, the spines on the last whorl are converted into large, thick, laterally-com- 

 pressed, knob-like tubercles. The animal had, apparently, attained great age ; and, as 

 I am not aware of any similar specimen having been found, I am inclined to regard the 

 individual in question as a monstrosity rather than as a variety. 



The present shells much resemble V. atldeta in the character of the spines, and in 

 the conditions of the inner lip and the columellar folds; but the deep transverse fur- 

 rows, which continue to be strongly marked even in adult specimens, entitle them, ap- 

 parently, to specific distinction. 



Size. — Axis, ; diameter, 



Locality. — Bracklesham Bay. 



