584 
DE. CAEPEXTEE’S EESEAECHES OX THE rOEJAIIXirEEA. 
than that afforded by the transitory phases of types hitherto known only in their states 
of more advanced development*. It would be very unreasonable to put aside these 
cases as so far exceptional that no inferences founded upon them can have any apphca- 
tion to the higher forms of Animal and Vegetable life. For it is only in the degree of 
their range of variation, that Foraminifera and Proto^hyta differ from Yertehrata and 
Plianerogainia ; and the main principle which must be taken as the basis of the system- 
atic arrangement of the former groups, — that of ascertaining the range of variation 
by an extensive comparison of individual forms, — is one which finds its application in 
every department of Natural History, and is now recognized and acted on by all the 
most eminent Botanists and Zoologists. It will be sufficient for me here to refer to the 
views recently advanced by Dr. J. D. Hookek in his “ Introduction to the Flora of 
Australia ; ” the results of his extensive experience in the comparison of the Floras of 
different portions of the globe having led him to conclusions regarding the probable 
origin of the diversities they present, with which my own deductions from the study of 
the Foraminifera are in complete accordance. And I am authorized by !Mr. Thomas 
Davidsox, whose extensive knowledge of the BracMopoda enables him to speak as the 
highest authority upon all that relates to that most interesting group (which, like the 
Foraminifera, is traceable through the entire series of fossiliferous rocks), to state that 
in proportion to the increase of his knowledge of its modifications of type, does he find 
reason to regard many of them as haHng had so unde a range of variation, as fully to 
justify him in making a large reduction in the number of specific t;j'pes hitherto accounted 
distinct ; whilst in the same proportion he finds himself able to trace Muth considerable 
probability the same specific types through a succession of geological periods, — certain 
Oolitic and Cretaceous Terehratulidce^ for example, being the probable ancestors of 
existing forms; and even the Lingula of the Wenlock Silurians not being distinguish- 
able by any characters which he can recognize as constituting a valid specific difference 
from the Lingula anatina of our present seas. 
261. The following are the general propositions which it appears to me justifiable to 
base on the researches of which I have now given a rhume : — 
I. The range of variation is so great among Foraminifera, as to include not merely the 
differential characters Avhich systematists proceeding upon the ordinary methods have 
accounted specific, but also those upon which the greater part of the genera of this group 
have been founded, and even in some instances those of its orders. 
II. The ordinary notion of sgjecies as assemblages of individuals marked out from each 
other by definite characters that have been genetically transmitted from original proto- 
types similarly distinguished, is quite inapplicable to this group ; since even if the limits 
* It is among the lower Fungi that the researches of Tula.sxe and others have shown the greatest 
variability to prevail ; whilst tlie recent inquiries of Dr. J. Bbaxtok Hicks have brought to light a most 
unexpected relationship between the supposed Unicellular Algos and the Gonidia of Lichens. See his 
Memoirs in the Quarterly Journal of IMicroscopical Science, October 1S60 and January 1861. 
