Zoological Illustrations Series II/Plate 53
VOLUTILITHES. Pl. 1.
1. Muricina. 2. pertusa.
VOLUTILITHES muricina.
Family, Volutidæ. Sub-Family, Volutinæ. Nob.
(Genus Voluta, Lam.)
Generic Character.
Spiral whorls regularly and gradually diminishing towards the apex, which is always acute. Plaits of the pillar numerous, always indistinct, generally evanescent, and sometimes wanting. Nobis.
Type, Voluta musicalis? Lam.
Specific Character.
Shell nearly fuciform, the base narrow and smooth; the upper part with longitudinal, subcostated, spinous plaits: inner lip thickened, the last plait on the pillar very thick, and separated from the others, which are slender, and nearly obsolete, by a deep groove.
Voluta Muricina. Lam. Syst. 7, 1, 350. Ency. Meth. pl. 383. f. 1.
The fourth principal division of the Lamarkian Volutes has hitherto been found only in a fossil state; unless, indeed, the Voluta Braziliana really belongs to this type. The species are very numerous, both in the London clay, and the Calcaire grossier of Grignon. They offer some beautiful types of form, representing the conterminous groups in this family, some of which we may hereafter notice more particularly. The pre-eminent type may probably be the V. musicalis of Lamarck; as yet, we only know this fossil from descriptions and figures, but it has obviously been confounded with several others.
Lamarck has given a character so exquisitely finished of V. muricina, that we have done little more than translate his words. Our specimen appears to be from Grignon, and was furnished to us with the following, by Messrs. Stuchbury, 33, Theobald's Road, Bedford Row.
VOLUTILITHES pertusa.
Shell subfuciform, and the base striated; the upper part with thick, remote, and somewhat nodulous ribs; traversed near the suture with lines of punctured striæ; inner lip thickened, plaits on the pillar distinct, the last very strong, the two next smaller, and the upper very slender.
This species is certainly undescribed by Lamarck, nor do we find it in Dr. Fleming's useful compendium of the "Mineral Conchology." Our specimen has the grey tinge of the London clay fossils. Neither of these species are typical; as they represent the recent costated Volutes, in the adjoining group.