468 
DR. MANTELL ON FOSSIL F0RAMIN1FERA. 
resemble the cluplicatures produced by the shrinking, or corrugation, of a flexible 
integument. The outline of the shell is but dimly visible, and can only be rendered 
apparent by a peculiar arrangement of the mirror of the microscope ; but it is suffi- 
ciently defined to show that the sacs occupy their respective chambers. As these 
two specimens are contained in semi-transparent flint, the appearances described may 
be supposed to have originated from the soft parts having undergone silicification, 
the brown endochrome of the original constituting the colouring material; but 
this hypothesis cannot be applicable to the following examples, all of which are 
from the Folkstone grey chalk. These are associated with numerous particles of 
transparent white and green quartz ; all vestiges of the shells having been destroyed 
by the acid. Fig. 5, is the body of a Rotalia deprived of its shell by the process pre- 
viously described; it consists of fourteen sacs, in their natural position, which are 
filled with a dark substance, and present no folds or corrugations, as do the empty 
sacs in other examples. At the part corresponding with the outer compartment, a 
considerable space is occupied by a pale transparent material, extending in patches 
beyond and below, and enveloping several dark globular bodies (a), that resemble in 
shape the ova of certain Gasteropoda. That these belong to the same animal seems 
probable from the occurrence of similar ova {a, a , a,) in the fossil represented, fig. 11, 
which is the body of a Rotalia seen foreshortened in the horizontal plane ; in this spe- 
cimen four large sacs are exposed, and these exhibit in a striking manner the folded 
condition of the integument of Avhich they are composed. The globular bodies ( ova ?) 
are twenty-one in number. 
The examination of the specimens above-described will elucidate the nature of 
the remarkable fossil delineated in fig. 10; a specimen, to which I would especially 
refer in confirmation of the opinion, that the appearances described can only have 
resulted from the preservation of the internal parts of the animalcules in an unmi- 
neralised state, like insects in amber ; at least no other interpretation occurs to me 
as affording so satisfactory an explanation of the phenomena under review. 
In this example the entire integument of the body of a Rotalia appears to be pre- 
sent, the shell having been wholly removed by the acid. The membrane of the 
largest sacs is very much corrugated, and disposed in numerous duplications, pro- 
bably from the empty state of those organs ; but the general contour of the original 
shell is preserved, and the inner subdivisions maintain an involuted discoidal arrange- 
ment. Some granules dispersed through a mass of light-brown matter, appear in the 
upper part of the specimen ; and on several of the sacs there are papillse, which may 
be regarded as indications of the bases of pseudopodia. The drawing so faithfully 
represents the original, that further description is unnecessary*. On this fossil I 
cannot forbear to observe, that this extraordinary preservation of the soft de- 
licate body of an animalcule invisible to the unassisted eye, through the innumerable 
* The shell of this specimen was probably of the same species as that represented in fig. 6. 
