The evolution theory . e hermaphrodite and livepartly in, partly uj)on crabs and hermit-ciabs (Fig. 112, C, Sacc).These hermaphrodites indeed fertilize themselves, but in their youthII. E 242 THE EVOLUTION THEORY they are of distinct sexes, and the females are so constituted thatthey lay eggs for the first time just when the males of the currentyear are appearing. Thus the first batch of eggs liberated by thefemales are fertilized by the minute free-swimming primordialmales, but after that the females themselves develop testes, and thenfertilize themselves; the males die very soon after copula
The evolution theory . e hermaphrodite and livepartly in, partly uj)on crabs and hermit-ciabs (Fig. 112, C, Sacc).These hermaphrodites indeed fertilize themselves, but in their youthII. E 242 THE EVOLUTION THEORY they are of distinct sexes, and the females are so constituted thatthey lay eggs for the first time just when the males of the currentyear are appearing. Thus the first batch of eggs liberated by thefemales are fertilized by the minute free-swimming primordialmales, but after that the females themselves develop testes, and thenfertilize themselves; the males die very soon after copulation, and onlyappear the following year in a new generation. They are thereforefar from being mere historic reminiscences, vestiges of the early historyof the modern species, for they are the instruments of a regularcross-fertilization of the species, and therefore of a constant minglingof new ids in the germ-plasm. This is not the place to discuss themarvellous life-history of these parasites in detail: I can only say.
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Keywords: ., bookauthorthomsonj, bookcentury1900, bookdecade1900, bookyear1904
