CARPENTER ON THE STUDY OE THE FORAMINIEERA. 835 
examining entire casts of the Eoraminifera have, so unexpectedly, 
imparted. 
“ An entirely new and most valuable source of information in regard to the 
organization of the Foraminifera has recently been afforded by the discovery, first 
announced by Professor Ehrenberg in 1853, that their shells occasionally undergo 
an infiltration of silicate of iron, that completely fills, not merely their chambers, 
but their canal system, even to its minutest ramifications; so that if a shell thus 
infiltrated should itself undergo decomposition, a perfect internal cast remains of 
the original body of the animal, with its extensions throughout the shell. Of such 
casts it has been shown by Professor Ehrenberg that the Green Sands which 
present themselves in the various geological formation, from the Silurian system 
upwards, are in great part composed ; and his discovery has thus a twofold value, 
as, on the one hand, it places before us far more exact representations of the 
configuration of the animal body, and of the connections of its different parts, than 
we could obtain even from living specimens by dissolving away their shells with 
acid (its several portions being disposed to heap themselves together in a mass when 
they lose the support of the calcareous skeleton); whilst it also enables us to 
identify with greater certainty the types of Foraminifera, by which these casts were 
originally formed, notwithstanding the entire destruction of their shells. Jt was 
soon afterwards shown by Professor Bailey (U. S.), that a like process of infiltration 
is taking place at the present time over certain parts of the ocean bottom, and that 
beautiful internal casts are obtainable by treating with dilute acid Foraminiferous 
shells whose cavities have thus filled. By the application of this method to portions 
of Mr. Juke’s Australian dredgings, Messrs. W. K. Parker and T. Rupert Jones 
have obtained a series of internal casts of most wonderful beauty and completeness, 
which I have had the advantage of carefully examining ; and it is with great 
satisfaction that I can state that in no instance has this examination afforded me 
any other result, that of confirming the conclusions to which I had been previously 
led by the study of the shell.”—(p. 10.) 
Besides the original observations of Dr. Carpenter himself, 
which constitute, indeed, the chief portion of its contents, Iris 
treatise makes copious reference to the labours of other workers in 
tbe same field, especially of Max. Schultze, Williamson, and Carter. 
While tbe peculiar nature of tbe aid rendered by bis assistants, 
Messrs. Jones and Parker, to whose most painstaking inquiries tbe 
author has truly awarded tbe praise so justly their due, adds not a 
little to its value as a work of reference. Here, again, it is necessary 
that we should quote Dr. Carpenter’s words :—• 
“ I found, moreover, that notwithstanding the dissimilarity between the lines of 
inquiry pursued by myself on the one hand, and by my friends, Messrs. Parker and 
Rupert Jones on the other, they led to conclusions most singularly accordant. My 
own studies had been restricted to a limited number of types (for the most part 
collected by Mr. Jukes on the Australian coast, and by Mr Cuming in the Philippine 
Seas), which included, however, all the most complex and highly developed forms of 
recent Foraminifera ; and I had specially devoted myself to the elucidation of their 
structure and physiology, and to the careful comparison of their numerous varietal 
forms. Theirs, on the other hand, had involved the comparison of the zoological 
characters of vast numbers of representatives of nearly all the generic types of the 
group, fossil as well as recent, brought together from various parts of the world, 
from various depths in the ocean, and from various geological formations : but had 
not been prosecuted with the same minuteness in regard to the details of internal 
structure or to physiological relations.”—Preface, p. v. 
“ Not only, moreover, did there prove to be this complete harmony in our general 
results, but there was also a singular unity in the aggregate of the work we had 
respectively accomplished, each portion being, so to speak, the complement of the 
