THE "WOLFFIAN BODY. 



423 



mentally arranged ; two or three corresponding to each somite 

 in the region of the body in which they occur. 



The relations of the Wolffian body to the blood-vessels are 

 well seen in Fig. 165. The dorsal aorta, A, lies between the 

 two Wolffian bodies, and gives off branches which supply the 



ME 



Fig. 165. — A transverse section across the body of a Rabbit Embryo at the 

 end of the eleventh day. x 45. 



A, dorsal aorta. A"VV", lumbar artery. C, coelom, or body cavity. CH, notochord. 

 G-M, glomerulus of Malpighian body. GR, genital ridge. ;KC, Wolffian duct. KM, 

 tubule of WolflRan body. ME, somatopleure. MH, meseutery. If D, dorsal root of 

 spinal neiTe. IfE, spinal ganglion. 'N'N, ventral division of spinal nerve. W"W', 

 dorsal division of spinal nerve. ITS, spinal cord. WV, ventral root of spinal nerve. 

 WY, sympathetic ganglion. TI, intestine. "V, vein. VC, posterior cardinal vein. 



glomeruli ; while the posterior cardinal veins, VC, lie along their 

 dorsal surfaces, and give off numerous branches, which lie in 

 very close relation with the tubules, and from which the epi- 

 thelial cells of the tubules withdraw the excretory products. 



The Wolffian body increases rapidly in size, and soon becomes 

 more compact and of miwe definite shape. Its position and rela- 



