VI 
THE VOYAGE OF H.M.S. CHALLENGER. 
the Foraminifera. The abstract question has but little claim on our attention, but 
connected therewith are certain practical points which invite a moment’s consideration. 
From a purely biological standpoint, the views expounded by Dr. Carpenter and his 
colleagues, in the Introduction to the Study of the Foraminifera , 1 are for the most part 
incontestable, but they embody only one aspect of the subject. 
It has been said by Prof. Huxley, speaking of the classification of the Invertebrata 
generally, that we may expect “ the progress of knowledge will eventually break down 
all sharp demarcations and substitute series for divisions .” 2 Abundant evidence may 
be found in the pages of the present Keport of the completeness of the morphological 
series in certain families of the Foraminifera. In some families not merely reputed 
species but reputed genera are connected by a close array of intermediate modifications, 
with characters differing only in degree of development, as well as by dimorphous forms 
in which the typical features of allied genera are combined ; and in such cases it is 
not too much to say that “all sharp demarcations” have ceased to exist. There are 
other groups, however, in which, possibly owing to our defective knowledge, the 
successive modifications appear to be less closely connected and to possess distinctive 
characters of greater persistence. 
But admitting the intimate relationship which often prevails throughout an entire 
generic group, admitting even that all the members of a genus may be referred to a 
common ancestral type, the question still remains how the different terms of each series 
are to be recognised. The various modifications which have been referred to differ not 
merely in details of form and structure but in habit ; they are met with under diverse 
conditions as to latitude, depth of water, nature of sea-bottom, and the like, and their 
modes of life are often totally distinct ; furthermore, fossil specimens with similar 
peculiarities appear to have existed under precisely corresponding circumstances. Whether 
“ species ” or not, the more important of them possess characters which afford means of 
easy identification, and it is obviously necessary that they should be provided with 
distinctive names. It only remains therefore to be determined what system of nomen- 
clature is to be pursued. 
An attempt has been made by Messrs. Parker and Jones, in their elaborate memoir 
on North Atlantic Foraminifera, to indicate the complicated relationship of the various 
modifications of the generic and subgeneric types, by the names assigned to them. The 
result is interesting from a biological point of view, but cannot be regarded as otherwise 
satisfactory. Such terms as “ Lag ena sulcata, var. (Entosolenia) globosa” or “ Pulvinulina 
1 “ The ordinary notion of species as assemblages of individuals marked out from each other by definite characters 
that have been genetically transmitted from original prototypes similarly distinguished is quite inapplicable to this 
group ; since, even if the limits of such assemblages were extended so as to include what would elsewhere be accounted 
genera, they would still be found so intimately connected by gradational links that definite lines of demarcation 
could not be drawn betwe en them.” — Introd. Foram., preface, p. x. Passages of similar import occur at p. xi, p. 56, 
and elsewhere in the same work. 
2 Journ. Linn, Soc. Loncl., vol. xii. (Zoology) p. 226, 
