This was an early description of a process of one kind of geographic speciation. In 1942 it was reintroduced by Mayr, and the importance of geographic speciation became one of the core ideas of the evolutionary synthesis.
ð ɪ s WORD_BOUNDARY w ʌ z WORD_BOUNDARY ʌ n WORD_BOUNDARY ɜː l i WORD_BOUNDARY d ɪ s k ɹ ɪ p ʃ ə n WORD_BOUNDARY ə v ə WORD_BOUNDARY p ɹ ɑ s ɛ s WORD_BOUNDARY ʌ v WORD_BOUNDARY w ʌ n WORD_BOUNDARY k aɪ n d WORD_BOUNDARY ʌ v WORD_BOUNDARY d̠ʒ ɪ ə ɡ ɹ æ f ɪ k WORD_BOUNDARY s p iː ʃ ɪ eɪ ʃ ə n WORD_BOUNDARY ɪ n WORD_BOUNDARY n aɪ n t iː n h ʌ n d ɹ ɪ d WORD_BOUNDARY f ɔ ɹ t i WORD_BOUNDARY t uː WORD_BOUNDARY ɪ t WORD_BOUNDARY w ʌ z WORD_BOUNDARY ɹ iː ɪ n t ɹ ə d uː s t WORD_BOUNDARY b aɪ WORD_BOUNDARY m eɪ ə ɹ WORD_BOUNDARY æ n d WORD_BOUNDARY ð ɪ WORD_BOUNDARY ɪ m p ɔ ɹ t ə n s WORD_BOUNDARY ʌ v WORD_BOUNDARY d̠ʒ ɪ ə ɡ ɹ æ f ɪ k WORD_BOUNDARY s p iː ʃ ɪ eɪ ʃ ə n WORD_BOUNDARY b ɪ k eɪ m WORD_BOUNDARY w ʌ n WORD_BOUNDARY ʌ v ð ə WORD_BOUNDARY k ɔ ɹ WORD_BOUNDARY aɪ d iə z WORD_BOUNDARY ʌ v ð ɪ WORD_BOUNDARY ɛ v ə l uː ʃ ə n ɛ ɹ i WORD_BOUNDARY s ɪ n θ ə s ɪ s WORD_BOUNDARY