TRANSVERSE SECTIONS OF EMBRYO OF 12 MM. 



203 



glomerulus becomes continuous with the covering of the glomerulus itself, the 

 whole structure resembling closely that of a Malpighian corpuscle of the true kid- 

 ney. The space around each glomerulus is really the beginning of a Wolffian 



Nch. 



Vert. 



V. U. D. 



v.u.s. 



FIG. 122. PIG, 12. o MM. TRANSVERSE SERIES 5, SECTION 633. 



Ao, Dorsal aorta. EC, Ectoderm. G, Spinal ganglion. G.bl, Gall-bladder. Gen, Anlage of genital gland. 

 Li, Liver, tries, Somatic mesenchyma. msth, Somatic mesotheliumi ~N~, Spinal nerve. Nch, Notochord. 

 Om.maj, Omentum majus. Om.min, Omentum minus. Soni, Somatopleure. Sp.c, Spinal cord. St, 

 Stomach. Um, Umbilical cord. V.card, Posterior cardinal vein. V.C.I, Vena cava inferior. Vert, 

 Anlage of vertebra. V.U.D, Right umbilical vein. V.U.S, Left umbilical vein. W.B, Wolffian body. 

 X 22 diams. 



tubule. The spaces between the tubules are almost entirely blood-channels, and 

 are lined by endothelium, which, for the most part, is closely fitted against the 



