. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 134 HAMEL KT II distributions for the small tubules showed little change. However, a marked increase in the total number of cells per surface of germinal tubule was noted in January 1989. Thereafter, oocyte size and number progressively in- creased in the small tubules until 20 July 1989 when the size structure was virtually identical to that of the small tubules prior to spawning in 1988. The sharp reduction in >800 ^m oocytes in the large tubules during the 1989 spawning closely followed the changes in the large t
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 134 HAMEL KT II distributions for the small tubules showed little change. However, a marked increase in the total number of cells per surface of germinal tubule was noted in January 1989. Thereafter, oocyte size and number progressively in- creased in the small tubules until 20 July 1989 when the size structure was virtually identical to that of the small tubules prior to spawning in 1988. The sharp reduction in >800 ^m oocytes in the large tubules during the 1989 spawning closely followed the changes in the large tubules during the 1988 spawning. Buoyancy o/ Oocyles. Thirty three of the oocytes showed a positive floatability which clearly increased with di- ameter (Spearman rank correlation coefficient, r = , df: 32, P < ). This indicated that mm oocytes would move upward at a rate of 20-30 mm • min~'. The other four oocytes showed a slightly negative floatability, and we suspect that they were damaged (possibly the egg membrane was not intact) (Fig. 8). These observations indicate that spawned eggs will move to the surface of the water column. This agrees with the abundance of devel- oping Psolus fabricii embryos near the surface, as observed by divers during the 1989 spawning. Male reproductive cycle Spermiogenesis. The following five stages of spermio- genesis are used to quantify the seasonal changes in the small and large tubules (Fig. 9). (1) Post-spawning (Fig. 9A). The thickness of the tubule wall is at its minimum. In the sections, we observed elon- gated empty areas along the length of the tubules, sug- gesting the passage of gametes during spawning. A few residual spermatozoa are present, and no proliferating zone (containing spermatogonia, spermatocytes and spermatids) was present. (2) Recovery. The tubule wall is extremely thick and highly convoluted. The tubules contain small quantities of spermatozoa and scattered nutritive phagocytes. (3) Growth (Fig. 9B,
Size: 2232px × 1119px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
