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majority of insect-hunting birds, had their eyes placed 
somewhat laterally and not frontally, as in the anthropoids 
in carnivora and in owls and similar predatory birds. 
For, unless the two eyes could be simultaneously focussed 
on the same object the estimation of distance, which deter- 
mined the idea of size, could only take place by the knowledge 
of the effort made to secure the focus of one eye, instead of 
by the system of unconscious trigonometrical survey, which 
was one of the main sources of the knowledge of distance 
employed by frontal-eyed animals; unless, indeed, it were 
considered that the angle was measured first with one then 
with the other eye by quick movement of the head. 
With monocular vision, where the distance was not exactly 
known, a small object nearer the beholder might subtend a 
greater angle than a larger similar one further off, and, if 
unfamiliar, be mistaken for the greater. 
The idea of distance was one of the more slowly-acquired 
concepts ; but the eyes of the young of all animals were quickly 
taken by conspicuous pattern. 
Coloration, at one extreme, served to break up the apparent 
mass and protectively obscure it, while at the other it invited 
attention as some glaring label ; a Poison label, which would 
denote danger to the consumer of the contents of the object 
bearing it, and, as in the case of the Poison label, the danger 
would exist irrespective of the size of the ‘“label’’ and the 
object it protected. Perhaps it might not be too strong an 
assumption to consider that the young inexperienced enemy, 
tasting the gaudily-coloured, distasteful Acraa, would be 
impressed, more by the coloration—by the Poison label— 
than by the size of the object, and afterwards would avoid 
sinilary-coloured objects, which crossed its field of vision, 
without taking any conscious account of their size. 
December 2nd, 1903. 
The PrestpENT exhibited a series of photographs sent by 
Mr. A. H. Thayer to illustrate his views on the significance 
of the colours and patterns of butterflies’ wings. The insects 
had been photographed on masses of foliage and flowers, and it 
