. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 2 3 4 5 6 7 8 9 10 11 12 13 Age (month). *+ 0> O) c 3 0) §> j; 0 3 ^ ~j n < CL <D O 2 ^ 3 —i W 0 1 0 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Age (month) Figure 3. Linear regression between body length and age and standard error are shown for each age group. Mean months) and the length (in millimeters) of small-size and large-size groups, respectively. The regression equations are as follows: }'l = + (.VI). (/• = t = , n = 720, P < ) Yl = + (A'2), (/• = / =
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 2 3 4 5 6 7 8 9 10 11 12 13 Age (month). *+ 0> O) c 3 0) §> j; 0 3 ^ ~j n < CL <D O 2 ^ 3 —i W 0 1 0 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Age (month) Figure 3. Linear regression between body length and age and standard error are shown for each age group. Mean months) and the length (in millimeters) of small-size and large-size groups, respectively. The regression equations are as follows: }'l = + (.VI). (/• = t = , n = 720, P < ) Yl = + (A'2), (/• = / = , n = 259, P"2(12)(Fig. 3). The annual growth rates of Scaphechinus mirahilis in the first and second years are and mm/y. respec- tively (Brykov and Parasyna, 1979). Therefore, the growth rates of that species in the first and second years are respectively and times faster than those of 5. mai. and Scaphechinus mirahilis would be about times larger than S. mai at the same age. Thus, the devel- opmental rate of these two sand dollars should be com- pared by taking the actual-size pattern of S. mai and con- trasting it with a reduced-size (to 19%) pattern ofScaphe- chinus mirabilis. Dt 'velopmental stages and rate of oral plates Interambulacral plates separate in a specific order: posterior: posterior-right and posterior-left (whether pos- terior-right occurs second and posterior-left third or vice versa is still unclear): anterior-right; and anterior-left (Fig. 4A-F). Examination of the discontinuous interam- bulacral plates revealed that 5. mai had a pattern differ- ent trom that of Scaphechinus mirahilis when analysis was based on actual size. However, the full-size 5. mai pattern was similar to the reduced-size Scaphechinus mirahilis pattern (Fig. 5). This indicates that develop- ment of oral plates is age-dependent. One sample that was mm in length had clear out- lines of two rings on each plate (Fig. 6A, B). A model was constructed by as
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
