. Chimæroid fishes and their development. Fishes; Chimaeridae. *."⢠^ V '' ^^ ^ ^'^'^ ^ â 0 â ^^* Fig. 44.âDetail of late (ertilizalion stage, showing male nucleus in the process of approaching the egg nucleus. A club-shaped centrosome surrounded by astral rays appears at (right) side of nuclear membrane. X 475. Fig. 45.âDetail of section similar to the last. A well-marked vacuole (artifact?) appears at one end of nucleus. Fig. nucleus with aster from section similar to the preceding. Fig 45B.âSperm nucleus from stage similar lo foregoing. The center of aster is to be found
. Chimæroid fishes and their development. Fishes; Chimaeridae. *."⢠^ V '' ^^ ^ ^'^'^ ^ â 0 â ^^* Fig. 44.âDetail of late (ertilizalion stage, showing male nucleus in the process of approaching the egg nucleus. A club-shaped centrosome surrounded by astral rays appears at (right) side of nuclear membrane. X 475. Fig. 45.âDetail of section similar to the last. A well-marked vacuole (artifact?) appears at one end of nucleus. Fig. nucleus with aster from section similar to the preceding. Fig 45B.âSperm nucleus from stage similar lo foregoing. The center of aster is to be found in the section below present one. Fig. 46.âDetail of section shown in (ig. 34. Sperm nucleus has divided amitotically. This at first suggests a stage of copulating pronuclei. Fig. 46A.âEgg and sperm nuclei in apposition. Rays not conspicuous. Fig. 47. -Early prophase of segmentation nucleus. Two asters are present, one of which (the right) contains two centrosomes. Fig. 47A.âEarly segmentation stage. Section passing through segmentation nuclei. No surface furrows are as yet present. X 190- from capsules about as shown in plate iii, fig. i6. In the present account the stages may conveniently be referred to as early, middle, and late. An early stage is shown in surface view in plate iv, fig. i8, magnified about 15 diameters. This was drawn from a living egg and shows the germinal area somewhat misshapen, due to rupture of the vitelline membrane, f The germinal area is not sharply outlined ; it is the same color as the remainder of the egg, and * The egg at deposition is undergoing the first stage of segmentation, t This is conspicuous at this stage, glossy and 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 Dean, Bashford, 1867-1928. Washington, D. C. , Carnegie Institution of Washington
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectfishes, bookyear1906
