. The beginnings of embryonic development : A symposium organized by the Section on Zoological Sciences of the American Association for the Advancement of Science, cosponsored by the American Society of Zoologists and the Association of Southeastern Biologists, and presented at the Atlanta meeting, December 27, 1955. Embryology. Fig. 14. Profiles of heads of sea urchin spermatozoa. (From Afzelius, Z. Zellforsch., 1955.) a-b, Strongijlocentrotus droebachiensis; c, Psammechi- nus miliaris; d, Echinus esculentus; e, Echinocardhim cordatum. Afzelius (1955) has made electron microscope studies of t
. The beginnings of embryonic development : A symposium organized by the Section on Zoological Sciences of the American Association for the Advancement of Science, cosponsored by the American Society of Zoologists and the Association of Southeastern Biologists, and presented at the Atlanta meeting, December 27, 1955. Embryology. Fig. 14. Profiles of heads of sea urchin spermatozoa. (From Afzelius, Z. Zellforsch., 1955.) a-b, Strongijlocentrotus droebachiensis; c, Psammechi- nus miliaris; d, Echinus esculentus; e, Echinocardhim cordatum. Afzelius (1955) has made electron microscope studies of thin sections of spermatozoa of four species of sea urchin. They reveal that a rather dense acrosomal particle lies in the tip of the acro- somal region. Beneath this particle the nucleus shows a depres- sion or "cave" filled with material less osmiophilic than that of the particle (Figs. 14—15). In one species, Echinocardium corda- tum, the acrosomal region is elongated in a manner unusual for sea urchins (Figs. 14e and 15B). Nevertheless, the acrosomal particle occupies the apical position. Beneath the particle a long stalk is apparently filled with material like that of the "cave" in. 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 American Association for the Advancement of Science. Section on Zoological Sciences; Tyler, Albert, 1906-. Washington
Size: 1583px × 1578px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookpublisherwashington, booksubjectembryology
