Nummulita. MOLLUSCA. CEPHALOPODA. 23S 
15. L. concamerata . — Surface of the chambers glossy and 
smooth. 
Serpula con. M<mt. 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 of 
a subpeUucid white colour, with three irregular volutions, and numerous dis- 
similar concamerations ; the exterior whorl has about nine glossy and tumid 
cells, of unequal size, but usually a larger and smaller alternate. Diameter 
half a line. This very minute species is at once distinguished from S. lohata^ 
by possessing much more numerous and infinitely more minute chambers, 
which are smooth and glossy, and not of that frosted appearance the lobata is 
invariably found to be, when examined by a microscope.” The author whom 
we have quoted, was inclined to consider the adhesion of these species to co- 
rallines and other bodies as identifying them with the genus Spirorbis. They 
are not (at least the Lobatula vulgaris)^ however, cemented, but seem to ad- 
here by the intervention of some animal matter. 
Gen. nummulita. — Lenticular, with an internal dis- 
coidal multilocular spire, divided into numerous chambers 
by transverse imperforated septa, and covered by several 
plates, tne wail of each turn being complicated, extended 
and united on each side to the other discs. 
1. N. loevigata. — Convex on both sides, and smooth. 
Lamm% Syst. Vert. vii. 629. Park. Org. Rem. iii. 152. t. x. f. 13.— In 
the London Clay, Hubbington Cliff. 
Gen. VI. VERMICULUM.^ — Chambers gibbose, the mouth 
alternately at the opposite ends of the axis. 
16. V. intortum. — Mouth compressed, with a simple tooth 
attached to the proximal side. 
Serpula seminulum, Linn. Syst. i. 1264 — Serp. subovalis umbilico per- 
vio. 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 /gth of an inch, a little compressed, the external margin sub- 
acute. Three chambers are usually visible on one side, and four on the 
other, slightly striated across with the line of separation distinct. The tooth 
is a triangular thin plate, a little recurved at the tip, and so persistent as 
frequently to remain after the outer side of the chamber has been destroyed. 
17. V. ohlongum. — Mouth round, with a pedunculated fork- 
ed tooth. 
Mont. Test. Brit. 522. t. xiv. f. 9. Flem. Wern. Mem. iv. 565. t. xv. f. 4. 
— Common. 
Rather less than the preceding. Three chambers are usually visible on 
one side, and two on the other ; in the former the middle chamber is par- 
tially embraced by the outer ones, so that a shallow depression is formed at 
the outside of the line of junction. On the other side of the shell a similar 
