. Outlines of zoology. Zoology. DEVELOPMENT. 421 micromeres) above or towards the animal pole. The blasto- sphere, which is the final result of segmentation, invaginates to form a gastrula. Along the mid-dorsal line of the gastrula the ectoderm cells sink in slightly so as to form a groove. This is the medullary groove, which here follows an unusual course of development. Instead of immediately closing to form a canal, the groove sinks inwards, and the lateral ectoderm grows over it before closing takes place. Later, the groove. Please note that these images are extracted from scanned page ima
. Outlines of zoology. Zoology. DEVELOPMENT. 421 micromeres) above or towards the animal pole. The blasto- sphere, which is the final result of segmentation, invaginates to form a gastrula. Along the mid-dorsal line of the gastrula the ectoderm cells sink in slightly so as to form a groove. This is the medullary groove, which here follows an unusual course of development. Instead of immediately closing to form a canal, the groove sinks inwards, and the lateral ectoderm grows over it before closing takes place. Later, the groove. 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 Thomson, J. Arthur (John Arthur), 1861-1933. Edinburgh, Glasgow and London, H. Frowde and Hodder & Stoughton
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Keywords: ., bookauthorth, bookcentury1800, bookdecade1890, booksubjectzoology
