. A manual of elementary zoology . Zoology. EMBRYOLOGY 485 and by backward outgrowths to spaces in the metapleural folds. In the adult the^se latter spaces are represented by lymph canals of doubtful origin. The walls of the spaces give rise to mesodermal tissues around the mouth and in the metapleural folds and to the first myomere. The remaining mesoblastic somites all behave alike. They extend down- wards on each side (Fig. 364) till they meet below the 'â â ---(8% ^H if >rS^°^vS^ â /' myoc. 'â¢â â ".."" 1 viol iW/i^^^^M Â¥$3jk~~m-pl- wM§$ ,..... Wh-ent. [qVy^^^^^
. A manual of elementary zoology . Zoology. EMBRYOLOGY 485 and by backward outgrowths to spaces in the metapleural folds. In the adult the^se latter spaces are represented by lymph canals of doubtful origin. The walls of the spaces give rise to mesodermal tissues around the mouth and in the metapleural folds and to the first myomere. The remaining mesoblastic somites all behave alike. They extend down- wards on each side (Fig. 364) till they meet below the 'â â ---(8% ^H if >rS^°^vS^ â /' myoc. 'â¢â â ".."" 1 viol iW/i^^^^M Â¥$3jk~~m-pl- wM§$ ,..... Wh-ent. [qVy^^^^^ SS-"^^ â 'â â Vfci^ 0'^ \-S(«a ~j W&7~ent- Fig. 364.âTransverse sections of embryos of Amphioxus at successive stages later than that represented by 14 (Fig. 361).âAfter Hatschek. Gut or enteron; ;l., muscle plate; , mesoblastic somite; myoc, myoccele; ».c, nerve cord; «.^>., neural plate; nek., notochord; s£lc, splanchnoccele. The outer or somatic wall of each lies against the epiblast, together with which it is known as the somatopleure; the inner or splanchnic wall lies against the hypoblast and is known with it as the splanchnopleure. The longitudinal septum or ventral mesentery between the cavities of the two sides now breaks down, so that they become con- tinuous. Meanwhile there has formed in each of them a horizontal septum which divides it into a dorsal half 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 Borradaile, L. A. (Lancelot Alexander), 1872-1945. London : H. Frowde, Hodder & Stoughton
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectzoology, bookyear1920
