. The microscope and its revelations. FIG. GOl.—DlsrorliiiHi i/fiili/ilnrix i ItoKitlii/tt i-ftrians, Schultze),with its pseiulopodia extended. »i±J. A. which shows a cast of the sarcode-body of the animal. (>nthe other hand, we find in the nautiloid spire a tendency to pass(by a curious transitional form to be presently described) into theci/clictf mode of growth ; in which the original segment, instead ofbudding forth on one side only, developes (ji/mi/n all round, so thaia riny of small chaml)ers (or ehamberlets) is formed around theprimordial chamber, and this in its turn surrounds itse
. The microscope and its revelations. FIG. GOl.—DlsrorliiiHi i/fiili/ilnrix i ItoKitlii/tt i-ftrians, Schultze),with its pseiulopodia extended. »i±J. A. which shows a cast of the sarcode-body of the animal. (>nthe other hand, we find in the nautiloid spire a tendency to pass(by a curious transitional form to be presently described) into theci/clictf mode of growth ; in which the original segment, instead ofbudding forth on one side only, developes (ji/mi/n all round, so thaia riny of small chaml)ers (or ehamberlets) is formed around theprimordial chamber, and this in its turn surrounds itself after t lielike fashion with another ring; and by successive repetitions of thesame process the shell conies to have the form of a disc made up ofa great, number of concentric rings, as we see in Orbitolites (tig. )and in (i/rtl<in / <//-i»i-(// were made by ace I 18 11 • • . j| 0 , . <•. \ Hollick liLh. .vm Wilson,C ATYPICA] rpon ;RAMIK i . °6. FOBAMINIFERA 799 M. dOrbigny the foundation of his classifie&,tion of this group,which, though at one time generally accepted, has now been aban-doned by most of those who have occupied themselves in the studyof the Foraminifera. For it has come to be generally admitted thatplan of growth is a character of very subordinate importanceamong the Foraminifera, so that any classification which is primarilybased upon it must necessarily be altogether unnatural, thosecharacters being of primary importance which have an immediateand direct relation to the physiological condition of the animal,and are thus indicative of the real affinities of the several groupswhich they serve to distinguish. The most important of thesecharacters will now lie Two very distinct types of shell structure prevail among ordinaryForaminifera—namely, the porcellanous and the Jii/olinf or shell of the former, when viewed by r
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
