153 
N. glohularia. This species is smooth and subglobose, and is de- 
scribed by Lamarck as being of the size of a full-grown pea. The 
specimens which I have, answering to the definition of Lamarck, are 
so very small, that although I have broken several, to obtain a view of 
their internal structure, I have not yet completely succeeded. It 
however appears to resemble that of the preceding species. 
N. scabra. This fossil is lenticular, the surface irregularly 
sprinkled with scattered points. 
This nummulite, M. Lamarck observes, is rather more convex on 
both sides than the smooth nummulite is ; but its surface is not 
smooth, like that of the two preceding species. In some, he 
observes, the surface is beset with small tubercles, or elevated 
points ; in others, with short projecting lines ; and in others, both 
the points and lines are observable. 
I am not able to assert, what I believe to be the case, that all the 
different species of this genus have their outer surface nearly smooth; 
but I have sometimes seen nummulites, whose inner plates were sca- 
brous, have a tolerably smooth external surface ; and I have re- 
peatedly seen the smooth nummulite, with internal plates marked 
with linear scabrous projections. The fact, I believe, is, that these 
different markings are all remains of the processes connecting the 
plates, and are so many different variations in the mode of partially 
connecting these plates ; perhaps by a substance, which, in a living 
state, possessed some degree of elasticity, and which would, there- 
fore, allow of some little change in the relative position of these plates. 
Struck with the peculiar appearance of the nummulite, Plate X. 
Fig. 18, it being of an irregular tumid shape, a reddish hue, and a 
slightly scabrous surface, I rubbed it down, so as to obtain a polished 
surface, in a longitudinal direction. On examining this surface with a 
magnifying glass, I was surprised at finding it yielded so very different 
an appearance from that which was seen in the section of the preceding 
VOL. III. v 
