The Monthly MlCTOscoplcal"] 
Journal, January 1, 1869. J 
Deejo-sea Protozoa. 
37 
these facts, therefore, with another very important one, namely, that 
perfect CoccospJieres are to be met with of every intermediate size 
between the ^Jo^^h and g^th of an inch in diameter or length,* I 
am induced to believe that the free Coccoliths are formed in every 
instance on, or jpari passu with, the spheroidal cells on which they 
rest ; the state of attachment to these cells being the normal as well 
as pristine condition. That they revert at any future stage of their 
life history, after once becomming free, to their original composite 
state, there is no recorded evidence forthcoming to prove. 
The question here arises, have these bodies any intimate con- 
nection with the origin or development of the Foraminifera of the 
deep-sea deposits ? Now, although the evidence on this head is very 
far from being conclusive, it is, I venture to say, sufficiently definite 
to countenance such a view. In some of the deposits in which both 
Foraminifera and Coccospheres abound, Coccoliths are to be met with 
arranged in an order so like that in which they occur on the Cocco- 
sphere cells, both on individuals of the Nodosarian Textularian, 
Rotalian, and Globigerine types, that no reasonable doubt can exist 
of their having more than a mere accidental relation to the surfaces 
they rest upon. Thus I have found, side by side, the perfect Cocco- 
sphere with its full complement of Coccoliths still adherent, and 
cells on which the number of persistent Coccoliths gradually dwindled 
down till only one or two remained, and it became impossible to 
determine whether I was looking at a Coccosphere cell or a 
" primordial segment " of a Foraminifer. In both cases (as formerly 
pointed out by me in * The Annals'f) the characteristic cross 
evoked by the polariscope is observable, whilst the density and 
specific texture of the cell or shell varies apparently with its age; 
until, in some specimens, we have actually presented to us the com- 
plete Foraminifer studded externally, throughout its surface, v/ith the 
Coccoliths in regular series. The subjoined extract is taken from 
of the Atlantic, I have dwelt on the striking diiference in character that exists 
between the immediate surface-layer of the sea-bed, and the stratum beneath ; and 
have pointed out why all living animal structures must necessarily be confined to this 
surface-layer. Although it is now too late to put the matter to the test — and a de- 
cisive opinion on the subject can only be formed by an analysis of the deposits the 
moment they are obtained— it would seem probable that the preponderance of 
perfect structures, as compared with their exuviae or debris, is to be accounted for 
on the supposition that, inasmuch as the former occur on the surface, whilst the 
latter become the sub-stratum, this preponderance when observable under the 
microscope, presents itself as a portion of the surface-layer or the sub-stratum 
happens to be examined. It is quite certain, moreover, that even in the case of 
the preserved specimens of deep-sea deposits, portions picked out from different levels 
present different relative quantities of these and other structures also. 
* As will be shown on a future occasion, some of tlie free-floating Coccospheres 
are oblong. It may be mentioned also that although I have here noted -g^jyth. of an 
inch as the largest observed size, very much larger specimens must in all probability 
exist, inasmuch as I possess mounted specimens of Coccoliths which themselves 
measure g^th of an inch across their longest diameter. 
t ' Annals and Magazine of Natural History,' July, 1861, and January, 1SG2. 
