294 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jan. 4, 



and geologist which makes it convenient to give them a sort of 

 subspecific value and a binomial term. 



It has been doubted by some whether in this, the most variable, 

 because simplest, family of the animal kingdom, every variety should 

 not be distinguished by its own binomial appellation, — a plan that has 

 been followed almost to the full by many naturalists. In this, how- 

 ever, we cannot agree, for the unlimited multiplication of quasi-spe- 

 cific names, linked together by pseudo-generic titles, can only weary 

 the catalogue-maker, and throw obstacles in the way of the systema- 

 tist ; for it keeps up a false notion of the value of external characters 

 which are rarely essential, whilst no clue is thereby obtained to the 

 morphological law of each real specific type. Evidences of such law, 

 however, are not wanting when we carefully examine varietal forms 

 as they diverge, and, as it were, radiate, from a given central type. 



Though Linnaeus was somewhat parsimonious in giving names to 

 the microscopic shells which he knew, and though Ficbtel and Moll 

 partially indicated their great variability, and were cautious in 

 naming them, yet it was not until Dujardin demonstrated the nature 

 of the Khizopodous sarcode and its simple, non- differentiated cha- 

 racter, and until Williamson and Carpenter, taking up the study of 

 certain species, showed what extreme forms might be connected 

 together by innumerable gentle intermediate gradations, that any- 

 thing like a really scientific appreciation of these Microzoa may be 

 said to have existed. Our own experience of the wide limits within 

 which any specific group of the Foraminifera multiply their varietal 

 forms, related by some peculiar conditions of growth and ornamen- 

 tation, has led us to concur fully with those who regard nearly 

 every species of Foraminifera as capable of adapting itself, with 

 endless modifications of form and structure, to very different habitats 

 in brackish and in salt water, — in the several zones of shallow, deep, 

 and abyssal seas, — and under every climate, from the poles to the 

 Equator. Our principles of nomenclature, and the application of 

 them, may be seen in our papers on Foraminifera in the ' Annals 

 and Mag. Nat. Hist.' 



Remarks on the Materials of the Tabular Synopsis. — In arranging 

 our synoptical tables of the Mediterranean Rhizopoda, recent and 

 fossil, and in comparing their numerous specific and varietal forms 

 one with another, we have not confined ourselves to our collections 

 from this region, but have necessarily made comparisons of forms 

 from almost every part of the globe, from the Arctic and the Tropic 

 Seas, from the temperate zones of both hemispheres, and from shallow, 

 as well as deep sea-beds. Geologically, also, we have reviewed the 

 Foraminifera in their manifold aspects as presented by the ancient 

 faunas of the Tertiary, Cretaceous, Oolitic, Liassic, Triassic, Permian, 

 and Carboniferous times ; finding, to our astonishment, that scarcely 

 any of the species of the Foraminifera met with in the Secondary 

 Rocks have become extinct ; all, indeed, that we have as yet seen 

 have their counterparts in the recent Mediterranean deposits. This 

 is still more clearly found to be the case with regard to the Chalk of 

 Maestricht and the Tertiaries. 



