186 

ding the nature of Chalk, or of any more ancient Foraminiferal 
limestone, by the condition of its altered forms ; the evidence 
of their Organic origin being supplied by the microscopic exami- 
nation of specimens exhibiting the least evidence of change, and 
this evidence being not in any degree invalidated by the most com- 
plete mineralisation of particular examples. A large number of 
specimens of Ophicalcite have been submitted to me from various 
sources, as to some of which I have been able to say pretty con- 
fidently that they were originally Eozoic, but have been altered 
by subsequent metamorphism ; whilst others do not present any 
feature whatever which would lead me to assign to them an 
Eozoic origin. To assume that these last (of which the Strath rock 
may be an example) are to be placed in the same category with 
the Canadian Eozoon, and thence to affirm that because they are 
purely Mineral productions, 7¢ cannot be Organic, involves a 
petitio principit by which it would be perfectly easy to prove the 
same thing of Chalk. —Let me illustrate my position by a parallel 
case. I have lately demonstrated* the existence of a Foramini- 
feral structure departing much more widely than Eozobn does from 
any previously known type, in a class of globular bodies from 
one to two and a half inches in diameter, occurring in the Upper 
Greensand ; these having been previously regarded by experienced 
Geologists as mere Mineral concretions. Now, it so happens that 
the Magnesian Limestone of the North of England contains large 
masses of spherical concretionary bodies, bearing a strong 
general resemblance to Parkeria in internal structure as well as in 
outward form, but hitherto regarded, I believe universally, as 
Inorganic ; and a reasoner like Mr. Reade would argue in this 
way :—‘‘ Because impartial geologists have pronounced the Per- 
mian concretions undoubtedly inorganic, the Greensand spheres 
are so likewise; and Dr. Carpenter’s Parkeria becomes ex- 
tinct as a fossil.” But it likewise happens that the structural 
features which are most peculiar in /arkeria present them- 
selves also in a remarkable living Foraminifer recently obtained 
from great depths in the Porcupine dredgings ; so that the truly 
Foraminiferal nature of Parkeria cannot bea matter of the slightest 
doubt. And the only question now is, whether a careful micro- 
scopic examination of the minute structure of the Permian con- 
cretions may not afford, through its likeness to that of Parkeria, 
more or less definite indications of their Organic origin, ob- 
scured by subsequent metamorphism. The application is obvious, 
6. Iam equally zmable to admit that if a rock presenting all 
the characteristic features of the Canadian Eozoon were to be 
found shading off into one containing characteristic Liassic fossils, 
this would afford the least tittle of evidence against the Organic 
character of the former, As the Zzzgu/a of the ancient Siluria 
has, in the judgment of our most eminent Brachiopodist, come 
down unchanged to the present time, and as even the same 
varietal modifications of Foraminiferal types were existing in the 
Triassic period as now in the Mediterranean, I see no reason 
why we should limit Eozodn to the Laurentian epoch. When 
this subject was last discussed at the Geological Society, I ven- 
tured to say that it would not ip the least surprise me to find 
Eozoén, or something very like it, now existing on the deep- 
sea-bottom ; and the notion ‘was not treated by any of the 
eminent Geologists then present as having any @ fyio77 impro- 
bability. Since that time, the Coccoliths first discovered by 
Prof. Huxley, and the Coccospheres first observed by Dr. Wal- 
lich, in the Globigerina-mud, and afterwards recognised by Mr. 
Sorby jn Chalk, have been detected by Prof. Giimbel in Silurian 
rocks ; so that it is clear that the Biological cqndition of the 
deep sea has changed much less in vast periods of Geological 
time, than has that of shallower waters ; whilst the probability 
has now almost reached a certainty.that Rhizopodic life has been 
at least as largely concerned in the production of Calcareous 
deposits in earlier Geological periods, as sye know it to have heen 
in the later. 
7. Though Mr. Reade ‘‘ feels assured that whenever impartial 
Geologists take the question up, the fossil itself will become .ex- 
tinct,” his assurance is not borne out by the judgment of the 
large number of impartial Zoolgists, Continental as well as 
British, who have satisfied themselves, by a careful examination 
of my series of microscopic preparations, of the Organic nafure 
of the Canadian Eozo6n, and have authorised me to express their 
entire accordance in my interpretation of its phenomena. An 
eminent Professor in one of our own Universities used this em- 
phatic expression—‘‘The matter seems to me not to admit of 
hesitation, much less of doubt.” My last Continental visitor, 
Prof. Carus, who is well known to possess a comprehensive and 
* See my description of Parkcria in the Phil. Trans. for 1869. 
NATURE 

[ Fan. 5, 1871 
practical knowledge alike of Zoology, Palzeontology, and Mine- 
ralogy—assured me that having come without any prepossession 
on the subject, he left me with a /ull conviction of the justice of 
my views. The respect paid by such Naturalists as Professors 
Milne-Edwards, Carus, Lovén, Van Beneden, and Escher von 
der Linth,—typical representatives of the Science of France, 
Germany, Sweden, Belgium, and Switzerland,—to my own judg- 
ment in a matter as to which ¢Aey regard the special studies 
of a third of a century as giving me some claim to authority, 
may console me for the contemptuous repudiation of micro- 
scopic evidence in which Mr. T. Mellard Reade has thought 
it becoming to indulge. I am far from expecting, however, 
that anyone should pin his faith upon my own éfse déxit, 
supported though it be by the entire concurrence of my 
three fellow labourers in Foraminiferal investigation, Messrs. 
Parker, Rupert Jones, and H. B. Brady. And if it be thought 
that the decision of any tribunal of really ‘* impartial geologists ” 
is likely to carry more weight with the scientific public than that 
of the authorities I have cited, I am perfectly willing to go into 
the question with them ; provided, however, that such tribunal 
consists of, or at any rate includes, men who are sufficiently con- 
versant with the Microscopic appearances of undoubtedly Organic 
structures, to be able to recognise such appearances when they 
see them. One of the strongest opponents of the Organic 
origin of Eozon designated as ‘‘an agatized mineral” a section 
of a recent Nummuline shell, that exhibited a minute tubulation 
corresponding with that of the nummuline layer of Eozoon, 
which he had just before characterised in the same manner. 
Another attributed the production of a perfectly mineralised in- 
ternal cast of Po/ystomel/a in green silicate, from Capt. Spratt’s 
Aégean dredgings, to the working-in of mud. And a third has 
abstained from even looking at my specimens, though I have 
repeatedly expressed my willingness to give him an opportunity 
of examining them. Such are zof the judges before whom IL 
would consent to plead the cause of Zozodn. 
WILLIAM B. CARPENTER 
Mimicry zervsws Hybridisation 
ALLOW me space for a word or two in reply to Mr. Wallace 
and Mr. Butler’s observations on my papers on Mimicry and 
Hybridisation. 
There is only one point in my argument to which they have 
taken exception, and although, of course, I am not therefore 
entitled to assume that their silence on other points means assent, 
I may at least infer that in their view the point objected to is 
most Open to assault, and that if it were established, the reader 
may regard the rest with increased confidence. 
The objection is that the instances of hybridisation in plants 
which I have cited as parallel.to the cases of mimicry between 
the Danaids and Nymphalids were merely cases of hybridisation 
between species of the same genus or allied genera, whereas these 
butterflies are more distantly related. |The question, as thus put 
by these gentlemen, resolves itself into a question of comparative 
degrees of affinity, and Mr. Wallace, with his usual skill, tries to 
throw the onus of proof from his shoulders to mine. But with 
all submission we shall keep it where it naturally lies. He puts 
it that my argument rests on the assumption that hybridisation 
can take place between different orders or families, and quite 
logically (supposing me to have done so) objects to my making 
any such assumption in regard to insects, seeing that nothing of 
the kind has ever been observed in other animals or in plants. 
But I rest my argument on no such assumption. I ask no other 
measure for insects than is given to plants. It is Mr. Wallace 
who makes the assumption that the amount of difference between 
Lepidoptera has a different value from that attached to it in any 
other organic beings. It is he who claims for differences which 
in any other creatures would be regarded as ro more than specific 
the importance of generic or ordinal. But however this may 
suit the artificial classification of the systematist, we cannot allow 
it when we come to deal with the actual workings of nature. 
I am not surprised that either Mr. Wallace or Mr. Butler 
should take what appears to me an exaggerated view of the 
dignity and position of their favourite group. It is human nature 
that any subject to the study of which we have devoted ourselves 
should assume in our eyes larger proportions than it does in the 
eyes of those who take a wider but less detailed view of it. 
Tfence we see Mr. Butler comparing the Lepidoptera to birds, 
as if it were a kingdom of equal magnitude, and seeking for 

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