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. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. REPRODUCTION IN DROSOPHILA. 219 process is repeated in the spermathecae. Here it is still easier to follow their entrance, for the ducts of these receptacles are very thin and transparent. In no case were spermatozoa observed entering these receptacles before the ventral receptacle was filled with spermatozoa. This might be explained by the position of the orifice leading to the latter, which, as already stated, is placed a little posterior to the openings of the spermathecse, and per- haps also by the partial closure of the

. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. REPRODUCTION IN DROSOPHILA. 219 process is repeated in the spermathecae. Here it is still easier to follow their entrance, for the ducts of these receptacles are very thin and transparent. In no case were spermatozoa observed entering these receptacles before the ventral receptacle was filled with spermatozoa. This might be explained by the position of the orifice leading to the latter, which, as already stated, is placed a little posterior to the openings of the spermathecse, and per- haps also by the partial closure of the Stock Photo
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RHR6W8

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1813 x 1379 px | 30.7 x 23.4 cm | 12.1 x 9.2 inches | 150dpi

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. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. REPRODUCTION IN DROSOPHILA. 219 process is repeated in the spermathecae. Here it is still easier to follow their entrance, for the ducts of these receptacles are very thin and transparent. In no case were spermatozoa observed entering these receptacles before the ventral receptacle was filled with spermatozoa. This might be explained by the position of the orifice leading to the latter, which, as already stated, is placed a little posterior to the openings of the spermathecse, and per- haps also by the partial closure of the orifices leading to these organs. The spermatozoa contained in the seminal receptacles form bundles; in the ventral receptacle all the heads are directed toward the tip or free end of the organ. In the spermathecse the bundles are concentric. Once within the receptacles the spermatozoa cease to swim, showing only undulatory movements; in this condition they can live for many days, even weeks. 5. THE EGG AND ITS ENTRANCE INTO THE UTERUS. The eggs of Drosophila melanogaster are very small, elliptical in shape and bear at one end a pair of diverging appendages. FIG. 7. Dorsal and lateral views of the egg of D. melanogaster. a, appen- dages ; c, plate formed by the edge of o, transparent area resembling an oper- culum ; m, micropyle cone.. 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 work.. 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, Alfred Clarence, 1890-1983. Woods Hole, Mass. : Marine Biological Laboratory