153 



_ 

 A 7 , globularia. This species is smooth and subglobose, and is described 



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 sur- 

 face 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 repeatedly 

 seen the smooth nummulite, with internal plates marked with linear 

 scabrous projections. The fact, I believe, is, that these different mark- 

 ings 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, therefore, 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. X 



