Presidential Address. 



Fig. 2. — Similar section to that shown in Fig. 1, but stage 25. 

 The nerve trunk has increased much in size, and fibrillation is beginning to appear. 



Fig. 3. — Similar section ; stage 27. 

 The nerve trunk is now elongated : it is naked towards its central end ; non-nucleated ; distally 

 it is for some distance surrounded by heavily yolked sheath-mesenchyme ; its peripheral end is 

 now broken up into a fanlike arrangement which in places can be seen to be continuous with the 

 protoplasm of the myoblasts. 



m., Myotome: n., Nerve; s.c. Spinal cord: sh., Sheath. 



