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 the 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 it \nAmphlstegina and JVonionina^, 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. 



{ Transactions of the Microscopical Society, 1st series, vol. iii. p. 105. 



Ibid. 2nd series, vol. i. p. 87. || Annals of Natural History, 2nd series, vol. x. p. 161. 



