. The cell in development and inheritance. Cells; Cells. 146 FERTILIZATION OF THE OVUM enters (Fig. 74). Thus, the starfish &^g, according to Fol, pos- sesses before fertiHzation a peculiar protoplasmic " attraction-cone " to which the head of the spermatozoon becomes attached, and through which it enters the In some of the hydromedusae, on the other hand, the entrance point is marked by a funnel-shaped depression at the egg-periphery (Metschnikoff). When no preformed attraction- cone is present, an " entrance-cone " is sometimes formed by a rush of protoplasm tow
. The cell in development and inheritance. Cells; Cells. 146 FERTILIZATION OF THE OVUM enters (Fig. 74). Thus, the starfish &^g, according to Fol, pos- sesses before fertiHzation a peculiar protoplasmic " attraction-cone " to which the head of the spermatozoon becomes attached, and through which it enters the In some of the hydromedusae, on the other hand, the entrance point is marked by a funnel-shaped depression at the egg-periphery (Metschnikoff). When no preformed attraction- cone is present, an " entrance-cone " is sometimes formed by a rush of protoplasm towards the point at which the spermatozoon strikes the &^g and there forming a conical elevation into which the sperm- head passes. In the sea-urchin (Fig. 74) this structure persists only a short time after the spermatozoon enters, soon assuming a / — m n- a. 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 Wilson, Edmund B. (Edmund Beecher), 1856-1939. New York : The Macmillan company
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectcells, bookyear1896
