. Text-book of embryology. Embryology. Fig. 202. —Sagittal sections through the stomodaeum and proctodaeum of Doncuda crassipes. (After Hirschler.) A, through stomodaeum. B, through proctodaeum. a, anus ; ect, ectodermal cells; &nd, endodermal cells ; mes, mesodermal cells ; o, mouth. Fig. 203. — Diagrammatic representation of mid-gut of the embryo of Donacia crassipes showing its lateral pouches. (After Hirschler.) gl, lateral pouches. We must now consider the further development of the mesoderm. As the coelomic sacs increase in size they shrink away from the yolk and in this way there ar
. Text-book of embryology. Embryology. Fig. 202. —Sagittal sections through the stomodaeum and proctodaeum of Doncuda crassipes. (After Hirschler.) A, through stomodaeum. B, through proctodaeum. a, anus ; ect, ectodermal cells; &nd, endodermal cells ; mes, mesodermal cells ; o, mouth. Fig. 203. — Diagrammatic representation of mid-gut of the embryo of Donacia crassipes showing its lateral pouches. (After Hirschler.) gl, lateral pouches. We must now consider the further development of the mesoderm. As the coelomic sacs increase in size they shrink away from the yolk and in this way there arises a space on each side which is the lateral portion of the epineural sinus. The two lateral spaces in the abdominal region, where coelomic sacs of right and left sides are in contact with one another, form from the beginning a continuous cavity; but in the thoracic region they are converted into a single cavity by the disintegration of the mid-ventral plate of endoderm described above, thus giving origin to a median sinus by the joining of those of the right and left sides. The walls of the coelomic sac now begin to undergo differentia- tion. The outer wall where it abuts on the ectoderm is composed of a single layer of closely apposed cells; this is the rudiment of the. 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 MacBride, E. W. (Ernest William), 1866-1940; Kerr, John Graham, 1869-; Heape, Walter, 1855-1929. London : Macmillan
Size: 1405px × 1779px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpubli, booksubjectembryology
