PROSOBRANCHIATA. 153 



No. 91. Voluta elevata. Sowerby. Tab. XX., figs. 2. a — d. 



Voluta ambigua, Lamk. 1811. Ann. du Mus., vol. xvii, p. 77, No. 12. 



— — lb. 1822. Hist. nat. &c, vol. vii, p. 352, No. 12. 



— — Desk. 1824-37. Descr. des coq. foss., vol. ii, p. 691 ; t. 93, figs. 10, 11. 



— elevata, Sow. 1840. Min. Conch., vol. vii, p. 7 ; t. 613, fig. 4. 



— ambigua, Gratel. 1845. Conch, foss. &c, du bassin de l'Adour, Supp. Volutes, t. i, 



figs. 14, 15. 



— — If Arch. 1850. Desc. des foss. du groupe Numm. (Mem. de la Soc. 



Geol. de Frai ze, 2d ser., vol. iii, p. 447). 



— — 1 Rouault. 1850. Desc. des foss. &c. des environs de Pau (Idem, 2d 



ser., vol. iii, p. 457). 



— sub-ambigua, If Orb. 1850. Prod, de Paleont., vol. iii, p. 10, No. 150. 



V. testa oblongo-ovatd, mb-twrritd, transversim sulcata, Jongitudinaliter costatd ; spird 

 elevata, acuta : anfractibus convex iusculis, ad margines suturales planatis ; sulcis posticis 

 latioribus ; costis fere ad basin tendentibus, duas vel tres series spinarum dentiformium 

 inter sulcos posticos gerentibus : labro ad marginem crenulato; labio parum expanso ; columella 

 tri-plicatd. 



Shell of a lengthened oval form, longitudinally ribbed, transversely furrowed, deeply 

 notched at the base ; spire elevated with a small pointed apex : whorls slightly convex, 

 with the sutural margins depressed so as to form a narrow flat space, which runs round 

 the spire ; furrows numerous and regular until they approach the shoulder of the whorl, 

 where the last three or four become gradually wider ; the longitudinal ribs, which are 

 more or less numerous in different individuals, extend almost to the very base of the 

 whorl, and are surmounted by several rows of short tooth-like spines rising out of the 

 spaces which separate the posterior furrows. The outer lip is smooth within, and cre- 

 nulated on the margin by the transverse sulci ; the inner lip is but slightly spread out, 

 and does not extend backwards beyond the suture ; the columella bears three very 

 oblique folds, of which the anterior one is the largest. 



This species was founded on a shell from the neighbourhood of London ; it occurs 

 also at Bracklesham Bay, but in the specimens from that locality the spire is not so 

 elevated, and the shell is altogether shorter and broader. 



The French shells referred by Lamarck to Brander's Strombus ambiguus, belong to 

 the present species ; but in them, as in the Bracklesham Bay shells, the spire is less 

 elevated, and the shell is broader. In other respects they agree with the type. 



A beautiful series of this Volute was obtained from the Artesian well at Southampton 

 by Mr. Keele, for the use of which I am indebted to the kindness of that gentleman. 

 One of this series is represented by figs. 2 c, d ; figure 2 b is taken from a specimen 

 from Highgate. 



•20 



