VII.] 



THE LIMBS. 

 Fig. 68. 



199 



Section theough the Lumbar REaiON or an Embkto at 



THE END OF THE FOUETH DaT. 



n.c. neural canal, p.r. posterior root of spinal nerve with gan- 

 glion, a.r. anterior root of spinal nerve. A.O.C. anterior 

 grey column of spinal cord. A. W.C. anterior white column 

 of spinal cord just commencing to be formed, and not very 

 distinctly marked in the figure, m.p. muscle-plate, eh. 

 notoohord. W.R. "Wolffian ridge. A.O. dorsal aorta. V.c.a. 

 posterior cardinal vein. W.d. Wolffian duct. W.h. Wolffian 

 body, consisting of tubules and Malpighian corpuscles. One 

 of the latter is represented on each side. g.e. germinal 



