. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 0 DAVID G. ATWOOD ray formed between the third pair and the terminal podium as spines (N) de- veloped on the oral and aboral surfaces. Spines were larger and more numerous on the oral surface near the terminal portion of each ray (Fig. 7). Thirteen days after fertilization, the preoral lobe (PL) was reduced to a small thickening and light-colored pigment spots (PS) were evident on the oral and aboral surfaces (Figs. 8, 9). The thin membrane sealing the oral region ruptured in 50% of examined juveniles at fourteen days exposi
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 0 DAVID G. ATWOOD ray formed between the third pair and the terminal podium as spines (N) de- veloped on the oral and aboral surfaces. Spines were larger and more numerous on the oral surface near the terminal portion of each ray (Fig. 7). Thirteen days after fertilization, the preoral lobe (PL) was reduced to a small thickening and light-colored pigment spots (PS) were evident on the oral and aboral surfaces (Figs. 8, 9). The thin membrane sealing the oral region ruptured in 50% of examined juveniles at fourteen days exposing a small functional mouth (Fig. 10). All four pairs of tube feet on each ray were functional at this stage. The anus opened when the larvae were 16 days old. The larval preoral lobe was com- pletely absorbed by this FIGURE 12. Young sea star at 77 days. Yolk material was completely used up at 35 days and the young sea star appeared translucent. The fifth pair of podia (T) on each ray had developed distal to the fourth pair by this time (Fig. 11). Figure 12 shows the five functional pairs of tube feet and the well developed, muscular mouth of a 77-day-old sea star. The chronological development as discussed in the preceding text is sum- marized in Table I. Echinaster embryos increased in diameter from to mm within the first 6J hours after fertilization. By 6 days the larvae reached a length of mm (Table II). Growth rates based on ray lengths were employed when larvae attained a sufficient measuring size at 6 days. Juvenile ray lengths showed dra- matic increases between 6 and 10 days ( to mm) followed by a second burst of growth at 14 days ( to mm) (Table III, Fig. 13). Values for the ratio R/r are presented in Table III. Growth rates expressed by wet weights. 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 no
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
