. Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote. . Rs the contents of the egg- FIG. 90.—Generative organs of a Heteropod (Pterotra- chea) after R. Leuckart. a, Male-organs; T, testis- Vd, vas deferens. b, female organs; Oo, ovary ; albumen gland; Rs, receptaculum seminis; Va, va- gi ua. cell, and in a way which is not understood gives the impetus to the de- velopment of the egg. The cell structures from which the eggs and sperm arise are called sexual organs, for reasons which will be evi- dent in the sequel; the eggs being produced
. Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote. . Rs the contents of the egg- FIG. 90.—Generative organs of a Heteropod (Pterotra- chea) after R. Leuckart. a, Male-organs; T, testis- Vd, vas deferens. b, female organs; Oo, ovary ; albumen gland; Rs, receptaculum seminis; Va, va- gi ua. cell, and in a way which is not understood gives the impetus to the de- velopment of the egg. The cell structures from which the eggs and sperm arise are called sexual organs, for reasons which will be evi- dent in the sequel; the eggs being produced in the female organ or ovary, and the semen in the male organ or testis. The egg is the female, and the semen the male product. The structure of the sexual organs presents extraordinary diffe- rences and numerous grades of progressive complication. In the simplest cases, both products arise in the body wall, the cells of which give rise at determined places to ova or spermatozoa (Coelenterata). Sometimes they arise in the ectoderm (Hydroid-Medusze), sometimes in the entoderm (Acalepha, Anthozoa). A similar arrangement. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Claus, Carl, 1835-1899; Sedgwick, Adam, 1854-1913; Sinclair, F. G. (Frederick Granville), b. 1858. London, Swan Sonnenschein & co.
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Keywords: ., book, bookcentury1800, bookcollectionbiodiversity, bookdecade1890
