. Text-book of embryology. Embryology. VIII AETHEOPODA 255 appear m these, and when the yolk in the mid-gut is finally absorbed a cavity appears there also. The former cavities then open into the mid-gut cavity, and it is then seen that a secretion has been developed m each rounded pocket, and that these pockets are in fact glandular outgrowths of the mid-gut. Hirschler compares these outgrowths to the liver diverticula of Arachnida and Crustacea, they are transitory structures and soon disappear in the larva (Fig. 203). The inner end of the stomodaeum is enlarged and develops a ring-like thic
. Text-book of embryology. Embryology. VIII AETHEOPODA 255 appear m these, and when the yolk in the mid-gut is finally absorbed a cavity appears there also. The former cavities then open into the mid-gut cavity, and it is then seen that a secretion has been developed m each rounded pocket, and that these pockets are in fact glandular outgrowths of the mid-gut. Hirschler compares these outgrowths to the liver diverticula of Arachnida and Crustacea, they are transitory structures and soon disappear in the larva (Fig. 203). The inner end of the stomodaeum is enlarged and develops a ring-like thickening of ectoderm at its inner end; in later stages endoderm cells become closely pressed against this end, and individual cells wander in amongst the ectoderm cells; thus when the cavity of the stomodaeum finally coalesces with the mid-gut it is im- possible to tell where ectoderm ends and endoderm 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
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Keywords: ., bookcentury1900, bookdecade1910, bookpubli, booksubjectembryology
