. Animal biology. Zoology; Biology. B C "* E Fig. 69.—Diagram illustrating the life history of a scyphozoan jellyfish {Aurdia). A section of the body of a female animal is shown with gonads (A), from one of which an egg cell IS produced. This is fertilized by a sperm cell from another animal, passes through the two-cell and four-cell stages, later becomes a blastula (5), then a gastrula (C), which is sno-rni in section, and finally develops into a ciliated planula larva (D). After a time this becomes attached and changes to a scyphistoma (£), from which is developed a strobila {¥). Each e
. Animal biology. Zoology; Biology. B C "* E Fig. 69.—Diagram illustrating the life history of a scyphozoan jellyfish {Aurdia). A section of the body of a female animal is shown with gonads (A), from one of which an egg cell IS produced. This is fertilized by a sperm cell from another animal, passes through the two-cell and four-cell stages, later becomes a blastula (5), then a gastrula (C), which is sno-rni in section, and finally develops into a ciliated planula larva (D). After a time this becomes attached and changes to a scyphistoma (£), from which is developed a strobila {¥). Each ephyra (G) from this strobila is the young of another animal. the one individual exhibits all these types, while in other coelenterates asexual reproduction is often restricted to the polyps and sexual reproduc- tion to the medusae of the same species. Budding may by its repetition give rise to colonies consisting of many hundreds and even thousands of individuals. Medusae remain single, are usually either male or female, and shed germ cells into the water. While, as a rule, they exhibit sexual reproduction, jellyfishes may produce other jellyfishes by budding from the surface of the manubrium. When the sex cells unite in fertihzation, the embryo which develops grows into a ciliated free-swimming larva known as a planula, which, after its free life, settles down and becomes the parent individual of a hydroid colony. Among the scyphozoan jellyfishes occurs an interesting type of budding called sfrohilation (Fig. 69). The planula, after becoming. 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 Wolcott, Robert Henry, 1868-1934; University of Nebraska (Lincoln campus). Dept. of Zoology. New York ; London : McGraw-Hill Book Company, Inc.
Size: 1578px × 1583px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcoll, booksubjectbiology, booksubjectzoology
