Part 6

Figure 1A. A sagittal section of an embryo of approximately the age of the one shown in figure 1. x 43.

Figure 2. A dorsal view of an embryo with five pairs of mesoblastic somites.

Figure 2A. A sagittal section of an embryo of the stage shown in figure 2. x 43.

Figure 2B. A transverse section through the headfold of an embryo of the stage shown in figure 2. x 43.

Figure 3. A dorsal view of an embryo with about fifteen pairs of somites. x 20.

Figures 3A-3D. A series of transverse sections through an embryo of the stage of the one shown in figure 3. x 43.

Figure 4. A surface view of an embryo with about twenty pairs of somites. x (about) 15.

Figures 4A-4D. A series of transverse sections through the anterior end of an embryo of the approximate age of the one shown in figure 4. x 20.

Figures 4E and 4F. Two transverse sections through the thyroid gland of this stage; more highly magnified. x 102.

Figures 4G-4M. A series of transverse sections caudad to the preceding. Figure 4H, x 43; other figures, x 20.

Figure 5. A surface view, in profile, of an embryo at the time of the origin of the limbs. x (about) 5.

Figures 5A-5I. A series of transverse sections through an embryo of the age shown in figure 5. x 7.

Figure 5J. A composite drawing of reconstructions of the enterons of two embryos of the age of the one shown in figure 5. One reconstruction was in wax, from sagittal sections, the other was a plotted reconstruction from transverse sections. x 14.

Figure 6. A surface view, in profile, of an embryo with well developed manus and pes. x (about) 5.

Figure 6A. A reconstruction, plotted from transverse sections, of the enteron of an embryo of about the age of the one shown in figure 6. x 14.

Figures 6B-6H. Part of a series of transverse sections from which the preceding reconstruction was made. x 7.

Figure 7. A reconstruction of the enteron of an embryo of 42 mm. crown-rump length.

Figures 7A-7G. A part of the series of transverse sections from which the preceding reconstruction was made. x 7.

Figure 7H. A high power drawing of a portion of the wall of the oesophagus in the region of figure 7A. x 190.

Figure 7I. A high power drawing of a portion of the wall of the stomach in the region of figure 7C.

Figure 7J. A high power drawing of a portion of the wall of the duodenum in the region of figure 7D.

Figure 8. An outline drawing, from the ventral aspect, of the enteron of an embryo of 20 cm. length, at about the time of hatching; made from a dissection. x 1.

LETTERING FOR ALL FIGURES

a, head-fold of amnion. aa, anterior appendage. ac, anterior cardinal vein. aip, anterior intestinal portal. al, allantois. an, anterior nares. ao, aorta. ar, aortic arch. au, auricle. b, bulbus arteriosus. bc, body cavity. bd, bile duct. bd', opening of bile duct to liver. bd'', opening of bile duct to duodenum. blp, blastopore. bp, basilar plate. bs, bile-sac. bv, blood vessel. c, centrum of vertebra. ca, caudal artery. ce, caecum. ch, cerebral hemisphere. cl, cloaca. cm, circular muscle layer. cn, cranial nerve. cp, posterior choroid plexus. cv, cardinal vein. d, duodenum. dc, ductus Cuvieri. di, diverticulum of stomach. e, eye. ec, ectoderm. ec', thickening of ectoderm. en, entoderm. en', endocardium. ent, enteron. ep, epidermal layer of ectoderm. ep', epithelium. epi, pineal body. es, embryonic shield. f, fronto-nasal process. fb, forebrain. fg, foregut. g^1-5, gill clefts. gf^1-6, gill folds. gl, glomerulus. h, head-fold. gs, glottis. gz, gizzard. hb, hindbrain. hc, head cavity. hg, hindgut. ht, heart. i, intestine. i', stomach. il, large intestine. in, infundibulum. io, intromittent organ. ir, iris. it, iter. k, kidney. la, larynx. li, liver. lm, longitudinal muscle layer. ln, lens. lp, lp', etc., loops of intestine. lu, lungs. lv, lens vesicle. m, mouth. ma, manus. mb, midbrain. me, medullary canal. me', tip end of medullary canal. md., mandibular folds. mes, mesoderm. mes', myocardium. mf, medullary fold. mg, medullary groove. mk, Meckel's cartilage. ml, muscle layer. mp, muscle plate. ms, mesentery. mv, meatus venosus. mx, maxillary fold. myc, myocoel. n, nasal cavity. na, neural arch of vertebra. nc, neurenteric canal. nl, nervous layer of ectoderm. nt, notochord. o, ear vesicle. oc, optic cup. oe, oesophagus. on, optic nerve. os, optic stalk. ov, optic vesicle. p, pituitary body. pa, posterior appendage. pag, post-anal gut. pan, pancreas. pan', opening of pancreas. pc, posterior cardinal vein. pe, pes. pg, primitive groove. ph, pharynx. pip, posterior intestinal portal. pl, pelvis. pn, posterior nares. pr, pericardial cavity. ps, primitive streak. pt, pecten. py, pylorus. r, rib. rt, retina. s, somites. sc, spinal cord. se, spenethmoid cartilage. sg, spinal ganglion. sl, submucosa. sm, splanchnic mesoblast. sn, spinal nerve. so, somatic mesoblast. st, stomodaeum. sy, sympathetic nervous system. t, tail. ta, trachea. tg, thyroid gland. tn, tongue. to, tooth anlage. tr, trunchus arteriosus. tv, tv', third ventricle of brain. ty, thymus gland. u, umbilical stalk. v', v'', v''', first, second, and third cerebral vesicles. va, vascular area. vc, vocal cords. vm, vitelline membrane. vn, ventricle of heart. vp, velum palitum. vv, vitelline blood vessels. wd, Wolffian duct. wdo, opening of Wolffian duct. wr, Wolffian ridge. wt, Wolffian tubule. x, point of origin of bronchi. y, yolk. ys, yolk-stalk.

The Figures were printed on a series of 15 pages ("Plates") at the end of the book. Since the caption text has already been given in full, the individual Figure numbers will not be repeated here.]

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Errata

As seen in figure 6A the lungs are irregularly conical printed as 6a at the point marked X text [two occurrences] unchanged: capital letter not explained ep, epidermal layer of ectoderm. [. for ,] epi, pineal body. [epi not italicized]