. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. ACROSOME FILAMENT AND SPERM ENTRY 253 cipient cone (Fig. 20, b). In some instances, as the spermatozoon continued moving inward, filose projections arose from the cone and continued growing out- ward even after the sperm head had passed through the cone into the egg proper (Figs. 16-19). Some common variations in the cone are shown as they appeared in specific living eggs. The cone shown in Figures 16-19 never rose extensively above the egg surface. Sometimes a moderately slender projection would move outward like a sleeve a
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. ACROSOME FILAMENT AND SPERM ENTRY 253 cipient cone (Fig. 20, b). In some instances, as the spermatozoon continued moving inward, filose projections arose from the cone and continued growing out- ward even after the sperm head had passed through the cone into the egg proper (Figs. 16-19). Some common variations in the cone are shown as they appeared in specific living eggs. The cone shown in Figures 16-19 never rose extensively above the egg surface. Sometimes a moderately slender projection would move outward like a sleeve ascending the inmoving acrosome filament, and then retract after the sperm head had entered the cone, as in Figure 21, a-c. In this specimen the cone remained broad at the base throughout the entry process but often an initially. FIGURE 22. Variations in sperm entry, from sketches of living specimens, a-f, Thyonc briareus; g-h, Astcrias forbcsii. Acrosome filaments shown only to depth actually seen, a-b and c-d, successive views of two specimens, respectively; e, very slender cone embracing acrosome filament; f, acrosome filament within egg proper; g-h, from two specimens of A. forbesii, successive stages which preceded stage closely resembling that shown in f. broad base would retreat partly or wholly so that the only obvious external cone would be a single slender projection (Figs. 12-13, 14 and 22, a, c and e). Transi- tory changing dilations appeared along such cones (Figs. 12-13 and 14). The cones were sometimes so slender that they might easily have been called "filaments" by an observer not cognizant of the existence of the much more delicate acrosome filaments (Figs. 14, 22, a and e). There was also variation in the distance from the egg proper at which the sperm head entered the cone (cf. Figs. 22, b and d). In the specimen shown in Figure 22, c-d a column of hyaline protoplasm continued to grow outward for some time after the sperm head had passed into the eg
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
