186 
DR. carpenter’s RESEARCHES ON THE FORAMINIFERA. 
It may, however, be well here to remark in limine, that it obviously makes a most 
essential difference in our appreciation of the value of the characters afforded by the 
form, position, and multiplication of the apertures of communication between the 
chambers of the shell, whether we regard these as giving passage to an organ of such 
fundamental importance as an alimentary canal, or whether they merely serve for the 
connexion of the different segments by stolons of sarcode. For variations, which in 
the former case must be regarded as indicative of such essential differences, both in 
structure and function, as would rightly characterize distinct genera or even distinct 
families, may easily be admitted, on the latter view, to be of such comparatively 
trivial moment, as to rank no higher than specific characters, or perhaps even to be 
matters of individual difference. That the latter is the true view of the case, I have 
become completely assured in the course of my researches ; and I shall hereafter be 
able to adduce some curious illustrations of it. 
Turning now to the more recent History of research, I shall briefly notice those 
investigations which have done most towards the advance of our knowledge of the 
organization and physiology of the Foraminifera ; the mere collection, description, 
and systematic arrangement of new forms, without any such advance, being no more 
a feature of progress, than is the building-up of an edifice, which must necessarily 
fall, through the insecurity of its foundation, before it shall have been completed. 
The first series of these, made by Professor W. C. Williamson of Manchester, upon 
Polystomella crispa* * * § , not only established several important facts in regard to its 
minute structure, but may be regarded as having furnished the starting-point for all 
future investigations of a like kind. Among these facts were several that became of 
essential value to myself, in the inquiry on which I was engaged at the same time, 
in regard to the structure of Nummulites-, and served to confirm the inferences which 
I had deduced from the other features of that important type, as to its participation 
in tlie characters of the Foraminifera generally. In the course of that inquiry I made 
the discovery'}', not only of a most elaborate and previously-unsuspected structure in 
the shell itself, but also of a system of interseptal canals, which established a com- 
munication between the inner segments and the external surface, much more direct 
than that which they possess through the series of segments which form the outer turns 
of the spire. The existence of this system of canals has been verified, not merely in 
Nummulites by MM. d’Archiac and Haime {Op. cit.), but also in several recent types ; 
thus Professor Williamson has detected \im Amphistegina and Nonionina^, and more 
recently in Faujasina^ (which furnishes one of the most remarkable examples of it) ; 
whilst Mr. Carter of Bombay has discovered it in Operculina\\. My own inquiries, 
which have been carried-on with scarcely an intermission, from the time of my first 
* Transactions of the Microscopical Society, 1st ser. vol. ii. p. 159. 
t Quarterly .Journal of the Geological Society of London, vol. vi. February 1850, p. 22. 
I Transactions of the Microscopical Society, 1st series, vol. iii. p. 105. 
§ Ibid. 2nd series, vol. i. p. 87. 1| Annals of Natural History, 2nd series, vol. x. p. 161. 
