2o8 Journal of Comparative Neurology. 



to each muscle-spindle. Occasionally, while yet outside the 

 capsule, more often in the periaxial space, the spindle-nerves 

 undergo branching ; the resultant branches consist of one, two, 

 three, or even more, short internodal segments. These branches 

 course along the surface of the axial portion of the spindle, in 

 part outside, in part within the axial sheath and may here have 

 a straight or serpentine course or may be partly wound around 

 the axial portion of the spindle. Within the axial sheath, the 

 meduUated nerve fibers may lose their medullary sheath at once 

 or after passing a longer or shorter distance between the intra- 

 fusal fibers, where they may undergo further branching. The 

 non-meduUated continuations of the meduUated nerve fibers 

 break up into fine fibers, richly beset with large varicose en- 

 largements. These, the terminal branches, are in contact with 

 the intrafusal muscle fibers, along which they extend for longer 

 or shorter distances and may often be traced to the poles of the 

 muscle-spindle. In longitudinal sections of muscle-spindles. 

 Fig. 25 (double stained in methylene blue and alum carmine), 

 but especially in cross section, Figs. 26 and 27, it may readily 

 be seen that these terminal fibers are just outside of the sarco- 

 lemma of the intrafusal fibers, between it and the connective 

 tissue sheath surrounding these fibers. 



Snake. Our preparations showing the nerve endings in 

 the muscle-spindle of the snake were made by injecting the 

 methylene blue {\% solution in normal salt), through the heart. 

 Strips of the back muscles, in which, as Kiihne and Sihler have 

 shown, muscle-spindles may be found, were removed to a 

 slide. In these ribbon-like muscles, a muscle-spindle showing a 

 stained spindle-nerve may now and then be found; and we were 

 thus able to obtain a number of muscle-spindles showing the 

 ending of the spindle-nerves. The muscle-spindles of the snake 

 and lizard, as previously stated, are simple, containing only one 

 intrafusal muscle fiber, surrounded by a capsule and axial 

 sheath. One, or, at the most, two meduUated nerve fibers have 

 been traced to such a spindle, and, in the preparations obtained 

 by us, the nerve fiber usually enters the spindle at one or the 

 other pole. If two nerve fibers go to the same spindle, these, 



