Studies in the Theory of Descent, Volume I. Weismann August
der europäischen Tagfalter.” Stuttgart, 1873.
37
[Trans. Linn. Soc., vol. xxv. 1865, p. 9. R.M.]
38
It is certainly preferable to make use of the expression “metagenesis” in this special sense instead of introducing a new one. As a general designation, comprehending metagenesis and heterogenesis, there will then remain the expression “alternation of generation,” if one does not prefer to say “cyclical propagation.” The latter may be well used in contradistinction to “metamorphosis.”
39
40
The idea that alternation of generation is derived from polymorphism (not the reverse, as usually happens; i.e. polymorphism from alternation of generation) is not new, as I find whilst correcting the final proof. Semper has already expressed it at the conclusion of his interesting memoir, “Über Generationswechsel bei Steinkorallen,” &c. See “Zeitschrift f. wiss. Zool.” vol. xxii. 1872.
41
See my essay “Über den Einfluss der Isolirung auf die Artbildung.” Leipzig, 1872.
42
[In the case of monogoneutic species which, by artificial ‘forcing,’ have been made to give two generations in the year, it has generally been found that the reproductive system has been imperfectly developed in the second brood. A minute anatomical investigation of the sexual organs in the two broods of seasonally dimorphic insects would be of great interest, and might lead to important results. R.M.]
43
“Grundzüge der Zoologie.” 2nd ed. Leipzig, 1872. Introduction.