86 THE ESSENTIALS OF HISTOLOGY 



In voluntary muscle the nerves, which are always medullated, 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 Doyere). 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. 



