. Text book of zoology. Zoology. Fig. 24. a Titelline protoplasm, Human OTiim. membrane, h c nucleus.— After KoUiker. Fig. 25. Diagram of an ovum, with many yolk-apherules. d protoplasm, h, with the nucleus, c, chiefly accumulated at one pole. — After Hert- wig. ir-L a colossal size (Squalid^, Aves). In this case it frequently happens that most of the protoplasm, with the nucleus, accumulates at one pole, whilst the chief mass of the egg consists of yolk held together by the rest: or the protoplasm forms a thin layer over the whole surface, whilst the inside consists principally of deutoplasm
. Text book of zoology. Zoology. Fig. 24. a Titelline protoplasm, Human OTiim. membrane, h c nucleus.— After KoUiker. Fig. 25. Diagram of an ovum, with many yolk-apherules. d protoplasm, h, with the nucleus, c, chiefly accumulated at one pole. — After Hert- wig. ir-L a colossal size (Squalid^, Aves). In this case it frequently happens that most of the protoplasm, with the nucleus, accumulates at one pole, whilst the chief mass of the egg consists of yolk held together by the rest: or the protoplasm forms a thin layer over the whole surface, whilst the inside consists principally of deutoplasm (Insecta). The spermatozoon is, at first, a single small cell consisting of protoplasm with a nucleus, and it may remain in this condition (Fig. 26, 1) ; but 3 4 as a rule, when mature, it is not so simple: very frequently it con- sists of a thickened part, the head, and a long, thin, whip- like tail, by the lashing of which it moves actively along. The head consists of the mo- dified nucleus; the protoplasm merely forms the tail, which may be re- garded as a giant flagellum. This. 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 Boas, J. E. V. (Johan Erik Vesti), 1855-1935; Boas, J. E. V. (Johan Erik Vesti), 1855-1935. Lehrbuch der Zoologie. London, Sampson Low, Marston
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1896
