vi FORAMINIFERA OF THE CRAG. 
tigations connected with animals of very low organization, that they are not to be regarded 
as of the same importance as similar, but more permanent, marks would be in higher 
animals. The difficulty in determining species is enhanced by the fact, that, whilst on 
the one hand several distinct species may each present varieties so similar that they may 
be easily confounded, on the other hand the extreme variations in sub-specific forms may 
at first sight often appear of generic value.’ 
With these preliminary remarks we may proceed to the critical examination of the 
generic and specific forms which have been found in the Crag—endeavouring to distin- 
guish the essential from the non-essential characters, the typical from the aberrant, the 
specific from individual modifications, and holding in view the same principles of investi- 
gation, the adoption of which has led, during recent years, to so great an increase of our 
knowledge of the group, at the hands of Williamson, Carpenter, Reuss, and others. 
! We have sometimes thought that a passage in Whewell’s ‘ Philosophy of the Inductive Sciences,’ 
written, it is true, in reference to a far different subject, might have been written, mutatis mutandis, with almost 
equal truth of the nomenclature of the Foraminifera. Speaking of Haiiy’s nomenclature of the crystals of calcite, 
he says—‘“‘ The want of uniformity in the origin and scheme of these denominations would be no valid objection 
to them if any general truth could be expressed by means of them; but the fact is, there is no definite dis- 
tinction of these forms. They pass into each other by insensible gradations, and the optical and physical 
properties which they possess are common to all of them. And, as a mere enunciation of the laws of 
forms, this terminology is insufficient. Thus it does not at all convey the relation between the disalterne 
and the dinoternaire ; the former being a combination of the metastatique with the prismatique; the latter 
of the metastique with the contrastante; again, the contrustante, the mizte, the cuboide, the contractée, 
the dilatée, all contain faces generated by a common law, the index being respectively altered, so as to be 
in these cases, 3, $, +, 2, 3; and this, which is the most important geometrical relation of these forms, is 
not at all recorded or indicated by the nomenclature.’ 
Nortr.—A very valuable memoir on the English and Belgian Crag formations, by Mr. R. Godwin-Austen, 
F.R.S., has just appeared in the ‘ Quart. Journ. Geol. Soc. London,’ vol. xxii, part 3 (No. 87), p. 229. &e. 
It is full of important facts and sound philosophic disquisitions.— August, 1866. 
