

Fig. 18. Transverse section through the 

 spinal cord of a 76-hour chick embryo 

 showing the early development of a spinal 

 nerve. After Cajal. A, motor root; B, 

 sensory root; C, bifurcation of fibers of 

 sensory root, a, b, c, d, neurones in various 

 stages of differentiation. From Bailey and 

 Miller, Embryology. By permission of 

 William Wood and Co. 



