The development of the human body; a manual of human embryology . duct. These cords acquire alumen and at one end connect with the duct, while nearthe other end a condensation of the mesoderm of the ridge occurs to form a glomer-ulus into which a vesselextends from the neigh-boring aorta. The tu-bules rapidly increase inlength and becomecoiled, and the glomeruliproject into their cavi-ties, pushing in front ofthem the wall of the tu-bule so that the wholestructure has the ap-pearance represented inFig. 196. It seems probable thatprimarily the mesoneph-ric cords are arranged segmentally, a sing
The development of the human body; a manual of human embryology . duct. These cords acquire alumen and at one end connect with the duct, while nearthe other end a condensation of the mesoderm of the ridge occurs to form a glomer-ulus into which a vesselextends from the neigh-boring aorta. The tu-bules rapidly increase inlength and becomecoiled, and the glomeruliproject into their cavi-ties, pushing in front ofthem the wall of the tu-bule so that the wholestructure has the ap-pearance represented inFig. 196. It seems probable thatprimarily the mesoneph-ric cords are arranged segmentally, a single pair occurringin each segment of the body behind the pronephros as farback, probably, as the pelvic region, and hence the inter-mediate cell-mass from which the Wolffian ridge is formedmay properly be regarded as composed of nephrotomes,even though no surface indications of segmentation are tobe seen in it. The correspondence of the tubules with themyotomes becomes, however, early disturbed, partly asthe result of differences in growth of the two structures,. Fig. 196.—Transverse Section ofthe Wolffian Ridge of a ChickEmbryo of Three Days. ao, Aorta; gl, glomerulus; gr, genitalridge; mes, mesentery; mt, meso-nephrie tubule; vc, cardinal vein;Wd, Wolffian duct.—(Mihalkovicz.) THE MESONEPHROS. 365 but especially because a number of secondary and tertiarytubules develop in connection with each of the primaryones. Exactly how these additional tubules arise is alittle uncertain, some observers maintaining that theyare formed from the substance of the Wolffian ridge in thesame manner as the primary tubules with which they later
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectembryol, bookyear1902
