. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. RESPIRATION OF SPISULA EG<iS 115 The rate of development increases linearly between 18-23° C. At higher temperatures the rate of increase falls off. In order to secure a high respiratory rate, but at the same time not to operate too near the range of abnormal develop- ment, 21° C. was chosen for the experiments. The rate of development was de- termined by counting the number of nuclei and following their increase in number with time. Sections were made in order to study other embryological changes occurring. For nuclear c
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. RESPIRATION OF SPISULA EG<iS 115 The rate of development increases linearly between 18-23° C. At higher temperatures the rate of increase falls off. In order to secure a high respiratory rate, but at the same time not to operate too near the range of abnormal develop- ment, 21° C. was chosen for the experiments. The rate of development was de- termined by counting the number of nuclei and following their increase in number with time. Sections were made in order to study other embryological changes occurring. For nuclear counts, the method described by Zeuthen (1951) for Cionit eggs was found much superior to whole mounts of fixed and Feulgen-stained eggs. Zeuthen's method consists of a careful and gradual compression of the eggs under a cover slip by withdrawing the suspension medium with tissue. The compression prevents further cleavage. Under the phase contrast microscope, the nuclei appear to be bright blue and are easily counted. Sectioned material (10 /*) was obtained from eggs fixed in Zenker-formol, stained with toluidine blue and imbedded in paraffin. RESULTS Morphological changes during development The morphology of the shed Spisula egg and its changes upon fertilization have been described by Allen (1953), who followed the events up to 100 minutes after fertilization. The present study corroborates his findings and extends the ob- oS ^™ ^* ^^ WZS -IOCJ OJU. 00 i. 240 260 280 300 320 0 •-» «zo 100 CLEAVAGE CONTINUES ASYNCHRONOUSLY IN DIFFERENT PARTS OF THE EMBRYO. 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 not perfectly resemble the original Marine Biological Laboratory (Woods Hole, Mass. ); Marine Biological Laboratory (Woods Hole, Mass. ). Annual report 1907/08-1952; Lillie, Frank Rattray, 1870-1947; Moore, Carl Richard, 1892-; Redfield
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
