9°20 CEPHALOPODA. CONULARIA, 
We have, however, but four species. WV. levigatus, is peculiar to the London 
clay, was first met with in Stubbington Cliff, and has since been found in 
Bricklesom Bay, Sussex. The WN. elegans, occurs at Emsworth near Chi- 
chester, in a siliceous stone, associated with other extremely minute species of 
shells. The N. variolaria is found abundantly in the London clay, at Stub- 
bington ; and N. Comptoni, has been found at Earl-stoke. 
Following the idea of Sowerby, we have united the genera Nummudites and 
Lenticulina, under the appellation of Nummularia, containing some recent 
species, as the two distinguishing characters of Lamarck are common with the 
genera, but were overlooked by Sowerby. The small fissure between the edge 
of each septum, and the margin of the preceding volution, as also the small 
columns which penetrate the parallel axis from one side to the other, and 
which sometimes form protuberances upon the surface, prevail in both genera, 
The volutions present the appearance of having been completed, at diffe- 
rent periods of growth, by three or four chambers gradually diminishing from 
the centre, until the last one extends only to the margin of the preceding volu- 
tion ; and the chamber being closed by a convex septum, without a continuous 
margin, is not so easily detected in such species as have very small chambers 
in proportion to their diameter, as is the case with most of the Nummulites. 
The want of a large external chamber has led naturalists to suppose that the 
shells of this genus were entirely enveloped in the integuments of the animals, 
while in a living condition; and this idea is farther strengthened by no 
siphuncle having hitherto been detected in these fossils. 
The ancients considered Nummulites as petrified lentils. Strabo mentions a 
species which was found in Egypt near some of the Pyramids. 
TRIBE III.— ORTHOCERATA. 
Shell not spiral, — straight, or nearly so. 
Genus XVI.— CONILITES. — Lamarck. 
Generic Character. — Shell conical, straight, slightly in- 
flated, having a thin external crust distinct from the 
nucleus or alveole which it contains ; nucleus, multilocular, 
divided by transverse septa, which are somewhat separable. 
Conilites pyramidata. Plate II. fig. 32. 
This genus is distinguished from Belemnites, by its sheath being thin and 
not filled up with solid matter from the point of the nucleus to the apex of the 
sheath, as in Belemnites. 
Genus XVII. — CONULARIA. — Miller. 
Generic Character. — Shell conical, straight, or nearly so, 
hollow, multilocular, divided by transverse, imperforate 
septa; aperture half closed by an inflation of the lip ; apex 
solid, obtuse; external surface covered with fine strie. 
Conularia teres. Plate 11. fig. 37. 
Two species only of this exclusively fossil genus are known; the C. teres was 
found at Troutie Bank, near Glasgow; the other, C. quadvisulcata, has been 
found in Ironstone nodules in the Carboniferous limestone in Renfrewsbire. 
