138 



ALAN C. SUTTON 



12 



•flt- V 



Fig. 11 A spindle in a 175 mm. pig embryo. Here the placques are thinned 

 out along the annular nerve fiber, the whole of which is connected to a delicate 

 network of neurofibrils that surrounds the entire muscle fiber. (Obj. Leitz, 

 1/12 oil immersion; ocular 4.) 



Fig. 12 Fragments of a neuro-muscular spindle from a 150 mm. pig embryo. 

 .A.bove is part of a muscle fiber that has been teased out of a spindle. One ot the 

 placques, still retaining its nervous connection, hangs free from the right end ol 

 the muscle fiber. The lower drawings are of two of these placques, isolated 

 from the muscle fiber, before and after crushing. They show the granular nature 

 of the placques, and also how they can be separated from the wiry nerve filaments. 

 (Obj. Leitz, 1/12 oil immersion; ocular S.) 



