. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. J. DAVID GEORGE 12S 11S IDS 9S 8S 7S 6S s < 5S 3S g _ S 2S — IS T PT 1C MC EC 10 C. A-A-2°C —r 24 DAYS AFTER ~r 32 ~r 40 48 SPAWNING FIGURE 22. The effect of sea-water temperature upon the early development of S. viridis at 30%e. M = metamorphosed individuals; EC := early cleavage; MC = mid-cleavage; LC := late cleavage ; PT = pre-trochophore ; T — trochopore ; S = setiger stage. Open triangles — 2° C.; Solid circles = 10° C.; Open circles = 20° C. Effect of salinity on early development (at 2° C. and 10° C.) There was no
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. J. DAVID GEORGE 12S 11S IDS 9S 8S 7S 6S s < 5S 3S g _ S 2S — IS T PT 1C MC EC 10 C. A-A-2°C —r 24 DAYS AFTER ~r 32 ~r 40 48 SPAWNING FIGURE 22. The effect of sea-water temperature upon the early development of S. viridis at 30%e. M = metamorphosed individuals; EC := early cleavage; MC = mid-cleavage; LC := late cleavage ; PT = pre-trochophore ; T — trochopore ; S = setiger stage. Open triangles — 2° C.; Solid circles = 10° C.; Open circles = 20° C. Effect of salinity on early development (at 2° C. and 10° C.) There was no appreciable difference in the rate of development of eggs and larvae in cultures maintained at salinities varying from 10/£e to 30%o (Table II). At 5%0, however, growth was much slower, development proceeding at only half the rate at W%o to 30%0. Below 5%c growth was interrupted and proved to be a lethal salinity for eggs and larvae alike. The higher the temperature the more quickly the young stages died at the lower lethal salinities. The reverse was the case at the upper limit of salinity tolerance (45-50%e) where early stages survived longer at higher temperatures (for examples of similar behavior in other animals see Kinne, 1964). All growth ceased in cultures maintained at 45%o. DISCUSSION The data presented show clearly that the population of 5". viridis at Lawrence- town has a short, well-defined, breeding period at the end of March and beginning of April. The observations of Dean and Pettibone of gamete-laden worms in Connecticut and New Hampshire in February, March and early April, conform to this pattern. However, the statement in the unpublished manuscript of Moore that breeding occurs in July and August at Woods Hole is conflicting. Visits to Woods Hole in July of 1963 and 1964 failed to reveal any gamete-bearing speci-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readabili
Size: 1880px × 1328px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
