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VIII. 



AN EXPERIMENTAL STUDY OF THE FORAMINIFEEAL SPECIES 

 VFRNEUILINA POLYSTROPHA (REUSS), AND SOME OTHERS, 

 BEING A CONTRIBUTION TO A DISCUSSION "ON THE 

 ORIGIN, EVOLUTION, AND TRANSMISSION OF BIOLOGICAL 

 CHARACTERS."* 



By E. HERON-ALLEN, F.R.S.. 



AND 



A. EARLAND, F.R.M.S. 

 Plates XVI— XVIII. 



Read Apuil 12. Published DECEMnEU 29. 1920. 



It would be difficult to conceive within the whole vast range of natural 

 knowledge the existence of a subject lending itself more readily to dogmatic 

 expression and subtle phrase than that of " The Origin, Evolution, and 

 Transmission of Biological Cliaracters " ; but though it is always easy to 

 dogmatize, it is generally very difficult to pin an indi\'idual protagonist down 

 to a definite pronouncement. To avoid this reproach — to provide at the 

 outset a te.Kt or postulate wlierein our general view of the question is concisely 

 e.xpressed — we opened our contribution to the discussion which took place 

 under this "title " at the Bournemouth meeting of the British Association 

 with the following axiomatic statement : — 



" Variation from type in any group of organisms is either sporadic or 

 epidemic. If it is the latter, the variation becomes specific. Going a step 

 further, variation from species is likewise sporadic or epidemic ; if it is the 

 latter, the variation becomes generic." 



And so a circle, not wholly vicious, would seem to be closed, but it will 

 presently be seen that in our opinion it is not a circle, but a triangle — a 

 triangle which takes its place (not always a very firmly established one) among 

 a series whose inter-relations admit of wide-reaching, and often apparently 

 anomalous, results. 



We shall naturally confine our arguments to tlie group witli which we are 

 particularly concerned — the Foraminifera ; and we open the subject by 



• Held at the joint meeting of Sections D (Zoology) imd K (Botany), at the meeting of 

 the British Association at Bournemouth, 12th September, l!tl9. 



K.I.A. PROC, VOL. XXXV, SKCT. B. V^"] 



