. Quain's elements of anatomy . 804 FEAMEWOEK OF THE BODY. uniform blastemic cells derived from the parietal mesoblast, coveredsuperficially by the cuticular epiblast, which always presents at itsextremity a peculiar pointed or conical cap of thickened epidermis. (Seeilg. 703.) The development of the parts of the limb now referred to, both in itslarger features and in its histological characters, is nsually somewhatmore in advance in the anterior than in the posterior extremities. Fig. Fig. 703.—Transverse section of the body of the chick at the level of theANTEEiou EXTKEiiiTiES. (From E
. Quain's elements of anatomy . 804 FEAMEWOEK OF THE BODY. uniform blastemic cells derived from the parietal mesoblast, coveredsuperficially by the cuticular epiblast, which always presents at itsextremity a peculiar pointed or conical cap of thickened epidermis. (Seeilg. 703.) The development of the parts of the limb now referred to, both in itslarger features and in its histological characters, is nsually somewhatmore in advance in the anterior than in the posterior extremities. Fig. Fig. 703.—Transverse section of the body of the chick at the level of theANTEEiou EXTKEiiiTiES. (From Esmalc.) am, amnion in its ceplialic fold ; ep, epiblast; s??i, parietal mesoblast; vm, visceraljnesoblast ; sp, spinal marrow ; r/n, spinal ganglion and nerve roots ; vip, muscle-ijlate ;dp, deimal plate ; ch, notocliord, with vertebral matrix round it ; a, aorta (the twouniting into one); re, cardinal veins; w, mesentery and Wolffian bodies ; ae, anteriorextremities composed of mesoblast, m, and covered with epiblast thickened at the point;i, intestinal canal open below into the yolk sac ; hy, hypoblast. Attitude and position of the Limbs.—From the manner in which, theprimary lappeb or limb-plate grows from the side of the axial part of the trunk,ib is obvious that at first it must present a dorsal and a ventral surface, corre-sponding respectively with those of the embryo body, and if we trace the subse-quent changes which bring out the features of the later form, we shall find
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Keywords: ., boo, bookcentury1800, booksubjectanatomy, booksubjecthumananatomy
