86 THE ESSENTIALS OF HISTOLOGY 



In voluntary muscle the nerves, which are always niedullated, ter- 

 minate in special organs, the so-called end-plates. A medullated fibre 

 will branch two or three times before terminating, and then each 

 branch passes straight to a muscular fibre. Having reached this, the 

 primitive sheath of the nerve-fibre is continued into the sarcolemma of 

 the muscle, the medullary sheath stops short, and the axis-cylinder 

 ends in a close terminal ramification with varicosities upon its branches 

 (figs. 107, 108). This ramification is embedded in a granular nucleated 

 protoplasmic mass which liea between the sarcolemma and the cross- 

 striated muscular substance. In some cases the ramification is 

 restricted to a small portion of the muscular fibre, and forms with the 

 granular bed a slight prominence (eminence of Doyei^e). This is the 

 case in mammals. In the lizard the ramification is rather more 

 extended than in mammals, whilst in the frog it is spread over a 

 considerable length of the fibre. 



