256 THE ESSEX FIELD CLUB.
beautiful series of lantern-slides, many of them being coloured, and some
were striking examples of the new three-colour process of photography.
It is impossible to give in a short space, and without illustrative figures,
a report which would do justice to Prof. Poulton's admirable exposition of
a difficult subject. His remarks and examples extended over almost the
whole range of the theories of Mimicry of Bates and Muller among butterflies,
Protective Resemblance among caterpillars and other insects, and Agressive
and Protective Resemblance amongst crustaceans, reptiles, &c. Many striking
instances of "Warning Colours" were shown, and the speaker especially
dwelt on the expansion of the theory of common warning colours of Muller
brought about by the recent observations of Messrs. Marshall and Shelford.
Prof. Poulton also described the remarkable discovery of the American artist,
Mr. Thayer, which is illustrated in the models of birds in the British Museum
and in the Hope Museum, showing that the light colour of the under sides of
many birds and animals serves to practically render them invisible when
illuminated from above, as in nature. The lecturer suggested that these
models should be reproduced in the Club's Museum.
The President, in proposing a vote of thanks to Prof. Poulton for his
admirable lecture, said that they were particularly indebted to that gentleman
for having taken the trouble to come up from Oxford for the purpose of
addressing the Club, this being the third occasion on which the Hope
Professor had given them the pleasure of hearing from him the results
of his continued investigations in that field of biology which he had cultivated
with such distinction. The lecturer had referred in the course of his remarks
to his own (the president's) contributions to this subject, but he thought that
the best contribution he had ever made was the discovery of Prof. Poulton
himself. Referring to the different subjects dealt with by the lecturer he
emphasized the point so well brought out by. the magnificent illustrations
shown, viz., that it would appear as though natural selection had been at
work with an eye to artistic effect, picking out every detail of colour, pattern,
structure and attitude that could be made use of in adapting the animals to
their environment. It was impossible to say whether a species harmonised
with its surroundings unless it were seen under natural conditions, and large
and apparently conspicuous animals, such as zebras and giraffes, had been
shown to be really well adapted for concealment when among their natural
surroundings. He (Prof. Meldola) went on to say that he was glad of the
present opportunity of being able to make a public recantation of a view
which he had many years ago first broached at a meeting of the Essex Field
Club. He referred to the light or white colours of the undersides of birds and
animals. At the time when this subject was being discussed by the Club
(see Proc. E.F.C, vol. I., p. vi., and discussion in Nature, vol. 31, p. 505 and
32, p. 172) he had not realised that such an arrangement of colours could
possibly have the enormous effect in affording concealment that had now been
shown to be the case by the American artist, whose models of ducks in the
Natural History Museum at South Kensington and in the Hope Museum at
Oxford, of which Prof. Poulton had shown them photographs, were well worth
looking at. He thought that their own Museum ought to possess such models,
which were not very difficult to make.