April 27, 1871 | 
no doubt that it does), but they show that it has a most uphill 
game to play, and one in which it is improbable for it to win 
without help from some other principle. 
It may be objected to what I have alleged that the result of the 
marriages between the individuals of the original form a and the 
varieties 6 and c, will not be of the pure original form, but forms 
half way between that original form and the variety. This 
will often be the case, but then the improper form of a will have 
in future generations an increasing tendency to revert to the pure 
original. , 
3. Mr. Mivart has adduced the co-existence of closely similar 
structures of diverse origin as evidence that there isa law of 
Variability over and above the principle of Natural Selection. 
The argument appears to me worthy of great consideration. If 
variability be a force operating in every direction equally, it is 
very improbable that the course of any two variations should run 
parellel ; if on the other hand the tendency to variation operates 
along particular lines, then itis likely that the lines which repre- 
sent the course of separate varieties should run parallel. How 
do the facts stand? The placental and marsupial quadrupeds 
form two distinct groups which branched off from one another in 
very remote times, and yet the two groups have developed into 
classes and sub-groups so correspondent that their courses may 
best be described as two parallel zigzag lines. Such a fact almost 
necessarily involves the conception of one and the same force 
controlling each group, so as to make it pass along its respective 
course, just as the likeness of two oak trees implies a like in- 
herent force in each acorn, 
But this is not the only instance which Mr. Mivart adduces ; 
he produces the fact that there are two parallel bridges which 
span the space between birds and reptiles; and I desire to add 
this further fact not noticed by Mr. Mivart, that there are in like 
manner two parallel bridges between fishes and reptiles. As is 
well known, there still exists a small class of animals, half fish and 
half reptile, often known as the Amphibia. They possess lungs 
like reptiles, but like fish they have gills and the consequent 
modification of the hyoidal arch, and their fore limbs have what 
may be called a degraded and fishlike form. The Archegosauri 
are extinct creatures of the carboniferous strata—like the existing 
Amphibia, half repti'es, half fish ; like them they carried both 
gills and lungs, and like them they had the fore limbs in a de- 
graded condition. So far there is nothing to the point ; but to 
the foregoing must be added that the existing Amphibians area 
bridge between reptiles and the hard-boned fishes, which are the 
predominant modern class ; whereas the Archegosauri were a 
bridge between reptiles and the ganoid fishes, to which class 
they were related by the character of their teeth, the imperfect 
ossification of the internal skeleton, and the excess of ossification 
in the external skeleton (Owen’s Paleontology, p. 193, et seg.). 
This observation will remain true, even if it should be shown, 
as some naturalists expect, that the Archegosauri were a tadpole 
form of a more perfect reptile; for it can hardly be doubted 
that the immature form expresses the history of the perfect 
one, and shows by its likeness to the ganoid fishes the original 
relation to that class. 
It has often appeared to me, that there are striking parallel- 
isms in the three great groups of the Quadrumana. For in- 
stance, the vocal organs of the Hylobates or Gibbons of the 
Indian Archipelago present a close relationship to those of the 
Mycetes or Howlers of the South American forests. The noc- 
turnal and insectivorous habits of some of the American genera 
recall the like habits of most of the Lemurs: and again, the 
Baboons are related to the Anthropoid Apes in a way which 
suggests to the mind that the similarity of their forms is greater 
than the nearness of their kinship. 
There is no doubt that similar parallelisms may be observed 
‘n very many groups; and I think that many of those pheno- 
nena of likeness which Mr. Darwin would attribute to atavism 
nay as well be explained by the retention in each group of the 
force which was inherent in the original family from which both 
graups have proceeded. ; 
This sort of parallelism is well illustrated by a very common 
accitent ; a tire gets loose from a wheel ; but both it and the 
wheé pursue nearly parallel courses, except so far as they are 
operaed upon by different external forces. 
EDWARD FRY 
Protective Resemblances 
HAVINt read the various papers by Messrs, Bennett, 
Murray, Vallace, &c., in NATURE, and thinking that my 
NATURE 
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597 
observations made on plants and animals in various parts of 
Southern Africa may ke of some interest to your readers, I am 
rather hastily putting together a few facts, which it had been my 
intention to have worked up into an illustrated paper, but which 
may perhaps prove of most interest at present, while the discus- 
sion is still warm. 
I must own that I prefer the use of the general term ‘ pro- 
tective resemblance” to the special term ‘mimicry,” as the 
latter seems to imply a certain amount of intelligent volition, 
which in the instances cited by Messrs. Wallace, Bates, and 
Trimen, I believe does not apply, whereas there are, I believe, 
cases where instinct does come into play, not acting physiologi- 
cally as Mr. Bennett would seem to assert, but in the construction 
of disguises. 
Mr. Bennett’s argument appears to me as fully adverse to his 
own theory as to Mr. Bates’s, and if Mr. Murray’s theory is 
correct then it ought equally to apply to animals so widely 
different as ants and spiders. 
Protective resemblances appear to me to be capable of being 
roughly classed as general and special, though both run into each 
other. Of general resemblances there are so many that I hardly 
think it worth while to enumerate instances, I shall therefore 
confine myself to some examples of special protective re- 
semblances which I have noted. 
I. As to plants I believe protective or useful resemblances are 
far commoner than some writers seem to think. 
- That excellent observer Dr. Burchell, in his ‘‘ Travels,” vol. i., 
p. 10, remarks :—‘*On picking up from the stony ground what 
was supposed a curiously shaped pebble, it proved to be a 
plant, and an additional new species to the tribe of Mesembryan- 
themum, but in colour and appearance bore the closest re- 
semblance to the stones between which it was growing. On 
the same ground was found a species of the Gryllus tribe amongst 
the stones, and so exactly like them in colour and even in shape 
that it could never have been discovered had it not been 
observed just ata moment when in motion, and as if more com- 
pletely to elude notice it seldom stirred, and even then but 
slowly. 
“The intention of nature in these instances seems to have 
been the same as when she gave to the chameleon the power of 
accommodating its colour in a certain degree to that of the 
object nearest it in order to compensate for the deficiency of its 
locomotive powers. By their form and colour, this insect may 
pass unobserved by those birds, which otherwise would soon 
extirpate a species so little able to elude its pursuers, and this 
juicy little Mesembryanthenum may generally escape the notice 
of cattle and wild animals.” 
I may here remark that a great number of Karoo plants have 
tuberous roots of similar form and colour, and it is especially 
curious to notice that, amongst the Asclepiadez, many species, 
such as Raphionueme, which are found in the grassy country, have 
their tubers hidden beneath the soil, whilst others, which occur 
in the stony Karoo, such as, Brachystelma filiforme, have them 
above the soil, and so perfectly do they resemble the stones 
amongst which they are found, that, when not in leaf, it isalmost 
impossible to distinguish them. 
Of imitating plants I may mention Ajuga ophrydis, the only 
species of the genus in South Africa, which bears a striking 
resemblance to an orchid, as also does Jmpatiens capensis, 
another solitary species. I mention these especially because they 
are very striking, although I am not aware that they are in any 
way specially useful, noting, however, that the latter plant is 
much frequented by insects, often by similar species to those 
which frequent Angrecum and Mystacidium, plants affecting 
similar localities. 
I know of many similar resemblances between plants belonging 
to most different orders, but cannot say how far they are merely 
fortuitous, and I am anxious to avoid Mr. Bennett’s reproach of 
being ‘ ultra-Darwinian.” 
With respect to the orthopterous insect mentioned by Burchell, 
that excellent observer, Mrs. Barber of Highlands near Grahams- 
town, communicated a most interesting paper to the Albany 
Natural History Society ona ‘‘ Stone Grasshopper,” which varies 
according to the nature of the soil of the district it inhabits ; 
and I have in my collection numerous species of Locustidz 
collected in the Karoo, whose successful imitation to the soil is 
most remarkable. I may remark here, that many most singular 
species of insects lose half their interest when penned down in a 
collector’s cabinet. 
As mimicry amongst mammals and reptiles is noted as rare, I 
may mention instances of what appear to me to be cases. 

