( xiii ) 
every organism between various elementary constituents— 
call them what we please — the greater number of which were 
destined to take no part in the somatic structure of the adult 
organism, though they might still be transmitted in a latent 
condition, through the germinal material, to succeeding 
generations. To the revival into efficient activity, under 
exceptional conditions, of some of these usually latent 
" determinants " or " gemmules," he was inclined to attribute 
such remarkable instances of atavism as those now exhibited 
by Mr. Merrifield. 
Mr. Barrett said he was interested to find that one of the 
forced forms of L. sibylla was similar to a specimen he had 
seen which had emerged from the pupa during a thunder- 
storm. 
Mr. F. W. Frohawk, in connection with Mr. Merrifield's 
paper, exhibited a series of 200 specimens of F. C-album 
bred from one female taken in Herefordshire, in April, 1894. 
The series consisted of 105 males and 95 females, and 
included 41 specimens of the light form, and 159 of the 
dark form. 
Professor Meldola, in proposing a vote of thanks, to 
Mr. Merrifield, Dr. Dixey, and Mr. Frohawk, said that he 
was glad to think that the subject of Seasonal Dimorphism, 
which had been first investigated systematically by Weis- 
mann, was receiving so much attention in this country. He 
was of opinion that the results hitherto arrived at were quite 
in harmony with Weismann's theory of reversion to the 
glacial form and all the evidence recently accumulated by 
the excellent observations of Mr. Merrifield and others went 
to confirm this view as opposed to that of the direct action 
of temperature as a modifying influence. 
Mr. Merrifield, Mr. Barrett, and Dr. Dixey took part in 
the further discussion which ensued. 
Pa'pers, etc., read. 
Mr. Frederick A. A. Skuse communicated a paper entitled 
" On a Colour- variety of Heteronympha merope^ Fab., from New 
South Wales," and sent coloured drawings of the typical form 
and the variety for exhibition. The paper was as follows : — 
