. The development of the human body : a manual of human embryology. Embryology; Embryo, Non-Mammalian. 40 THE SEGMENTATION OF THE OVUM D) shows a very decided difference in the size of the cells of the two poles. In the ova of reptiles and birds the amount of yolk stored up in the ovum is very much greater even than in the amphibia, and it is aggregated at one pole of the ovum, of which it forms the principal mass, the yolkless protoplasm appearing as a small disk upon the. C D Fig. 18.—Stages in the Segmentation or Amblystoma.—(Eycleshymer.) surface of a relatively huge mass of yolk. The iner
. The development of the human body : a manual of human embryology. Embryology; Embryo, Non-Mammalian. 40 THE SEGMENTATION OF THE OVUM D) shows a very decided difference in the size of the cells of the two poles. In the ova of reptiles and birds the amount of yolk stored up in the ovum is very much greater even than in the amphibia, and it is aggregated at one pole of the ovum, of which it forms the principal mass, the yolkless protoplasm appearing as a small disk upon the. C D Fig. 18.—Stages in the Segmentation or Amblystoma.—(Eycleshymer.) surface of a relatively huge mass of yolk. The inertia of this mass of nutritive material is so great that the segmentation is confined to the small yolkless disk of protoplasm and affects consequently only a portion of the entire ovum. To distinguish this form of segmenta- tion from that which affects the entire ovum it is termed meroblastic segmentation, the other form being known as holoblastic. In the ovum of a turtle or a bird the first plane of segmentation crosses the protoplasmic disk, dividing it into two practically equal. 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 McMurrich, J. Playfair (James Playfair), 1859-1939. Philadelphia : P. Blakiston's son & co.
Size: 1632px × 1530px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookautho, bookcentury1900, bookdecade1910, booksubjectembryology
