( xiii ) 
existence of a dominant form in each group, the other com- 
ponents of which were capable of being arranged in a 
descending order of resemblance to it. That was scarcely 
borne out by the specimens. A group such as that shown 
from Panama presented several hypertelic pairs and did not 
support the idea that the species could be arranged in degrees 
of adaptation towards one particular model. Whilst the 
facts of geographical distribution afforded, in his view, 
a real objection to the Miullerian theory, he did not look to 
distribution alone as likely to have hada considerable share in 
the production of these groups.* It might have had some ; 
but their production might conceivably be due to a variety of 
causes, and not one alone. 
He had certainly intended his remarks on hypertely to be 
taken as a criticism of the Millerian hypothesis. 
However effective a destructive agency might be in pro- 
ducing change, directly it became non-selective, the resulting 
change must stop short at the point reached; and _ his 
argument was that the process of discrimination by birds, 
the only available agents, would be limited to the recognition 
of a group of associated forms as an inedible whole, and being 
superfluous if carried farther would not be exercised so as to 
bring about such minute resemblances as were often met 
with. Asan instance, he might mention the two Brazilian 
eroups, differing in the white or yellow colour of the apical 
spots of the forewing. ‘To use a rough illustration, a person 
whose object was to avoid the society of a policeman would 
betake himself off at the first sight of the familiar uniform 
and would not stop to decipher such minutiz as the distin- 
guishing number thereon. His view was strengthened by . 
the President’s admission that in Millerian groups there 
apparently did not exist the same necessity for exact 
imitation as was demanded in the case of Batesian mimics ; 
it practically conceded his point. 
Every one who had listened to the discussion must, he 
thought, be struck with the amount of doubt thrown on the 
* The objections to any explanation based on distribution alone 
have been forcibly stated by Fritz Miller himself. ‘“ Kosmos,” 
1882, p. 262. 
