X. Researches on the Foraminifera. 

 By WILLIAM B. CARPENTER, M.D., F.R.S., F.G.S. %c. 



Received May 21, Read June 14, 1855. 



PART I. 



CONTAINING GENERAL INTRODUCTION, AND MONOGRAPH OF THE GENUS ORBITOLITES. 



page 

 General Introduction 181 



Monograph of the Genus Orbitolites. 



Section I. History 187 



II. General Plan of Organization 193 



III. Physiology 206 



IV. Variations 213 



V. Essential Characters, &c 223 



VI. Species 224 



VII. Concluding Remarks 226 



General Introduction. 



1.HE tribe of Animals in regard to certain members of which I propose to offer to 

 the Royal Society the results of my detailed investigations, is almost unknown, save 

 by name, to many well-informed Naturalists ; and has only of late received even a 

 small measure of that attention, which its zoological and its geological importance, 

 and its physiological interest, may fairly claim for it. Of the bodies which are now, 

 on account of their general conformity to a certain plan of organization, grouped 

 together under the designation Foraminifera, the greater proportion, being spiral 

 rnultilocular shells, were long associated with Nautili and Ammonites, and were thus 

 ranked as Cephalopodous Mollusks in the classifications of LAMARCK and CUVIER ; 

 whilst a few others, bearing more resemblance to certain kinds of corals, seemed 

 naturally to take their places among Zoophytes. 



Down to a comparatively recent period, scarcely anything has been known beyond 

 the external characters presented by these testaceous or coral-like bodies ; 'their 

 internal organization has been very imperfectly examined ; of their intimate structure, 

 no attempt at elucidation has been made ; and as to the nature of the animals of which 

 they are the skeletons, the grossest misapprehensions and errors have prevailed. And 

 though many important steps have been recently made in this direction, it is obvious 

 that the methods which have been proposed for the classification of the large number 

 of forms (apparently distinct from each other) that have been collected, described, 



MDCCCLVI. 2 B 



