History of British animals - University of Guam Marine Laboratory

Nummulita. MOLLUSCA. CEPHALOPODA. 23315. L. concamerata.— Surface of the chambers glossy andsmooth.Serpula con. Mont. Test. Brit. Supp. 160.This species, found by Montagu on the coast of Devon, is thus described :" Shell suborbicular, compressed, flat beneath, slightly convex above, and ofa subpellucid white colour, with three irregular volutions, and numerous dissimilarconcamerations ; the exterior whorl has about nine glossy and tumidcells, of unequal size, but usually a larger and smaller alternate. Diameterhalf a line. This very minute species is at once distinguished from S. lobata,by possessing much more numerous and infinitely more minute chambers,which are smooth and glossy, and not of that frosted appearance the lobata isinvariably found to be, when examined by a microscope." The author whomwe have quoted, was inclined to consider the adhesion of these species to corallinesand other bodies as identifying them with the genus Spirorbis. Theyare not (at least the Lobatula vulgaris), however, cemented, but seem to adhereby the intervention of some animal matter.Gen. NUMMULITA. — Lenticular, with an internal discoidalmultilocular spire,divided into numerous chambersby transverse imperforated septa, and covered by severalplates, the wall of each turn being complicated, extendedand united on each side to the other discs.1. N. laevigata.— Convex on both sides, and smooth.Lamark, Syst. Vert. vii. 629. Park. Org. Rem. iii. 152. t. x. f. 13. — Inthe London Clay, HubbingtonCliff'.Gen. VI. VERMICULUM.—Chambers gibbose, the mouthalternately at the opposite ends of the axis.16. V. hitortura.— Mouth compressed, with a simple toothattached to the proximal side.Serpula seminulum, Linn. Syst.i. 1264— Serp. subovalis umbilico pervio,Walk. Test. Min. t. i. f. 1— Serp. ovalis, Adams, Linn. Trans, v.p. 4. t. i. f. 28, 29, 30.—Ver. in. Mont. Test. Brit. 520 Flem. Wern.Mem. iv. 564. t. xv. f. 3—Common on corallines and old shells.Size about ^th of an inch, a little compressed, the external margin subacute.Three chambers are usually visible on one side, and four on theother, slightly striated across with the line of separation distinct. The toothis a triangular thin plate, a little recurved at the tip, and so persistent asfrequently to remain after the outer side of the chamber has been destroyed.17. V. oblongum.— Mouth round, with a pedunculated forkedtooth.Mont. Test. Brit. 522. t. xiv. £ 9. Flem. Wern. Mem. iv. 565. t. xv. f. 4.— Common.Bather less than the preceding. Three chambers are usually visible onone side, and two en the other ; in the former the middle chamber is partiallyembraced by the outer ones, so that a shallow depression is formed atthe outside of the line of junction. On the other side of the shell a similar