Wilson, Motor Endings of the Frog. 7 



In the frog's muscle the nerve ending has no ground plate 

 in which the branches ramify. The ramifications are not local- 

 ized but are spread over a relatively large and apparently vari- 

 able area of the muscle fiber. Usually but one medullated 

 nerve ends in a muscle fiber, though two medullated nerves 

 may be seen at times and three have been described ; occasion- 

 ally two medullated nerve fibers and one non-meduUated and 

 much finer fiber may go to the muscle fiber. When more than 

 one nerve goes to a muscle fiber it is often possible to trace the 

 origin of these to the same nerve stem. In no case was there 

 even the suggestion of one of these fibers coming from a nerve 

 whose course lay distinctly apart from the others. If more 

 than one nerve go to the muscle fiber, the places where the 

 nerves enter into contact with the fiber are, if not always, at 

 least most frequently, in close proximity to one another. In 

 short, on the muscle fiber the area to which the entering nerves 

 apply themselves relative to the entire length of the muscle 

 fiber is limited. 



Several varieties of motor endings have been described. 

 Thus, there are the four or five types of Cuccati which Retzius 

 would reduce to two ; the one exemplified by the branching 

 plate, the other by the broad band. At present, any classifica- 

 tion must be but temporary ; with equal justification several 

 varieties may be classed as typical by one and rejected by 

 another. For example, one might well wish to add to the 

 types of Retzius that more strictly localized variety which 

 DoGiEL has described and which occurs not unfrequently in cer- 

 tain muscles — a variety which closely resembles the branching 

 of mammalian nerve endings only without an end plate. ^ 



There is, however, one type which is generally recognized 

 as predominating — das Stangcn-gezveih of Kuhne. In it the 

 nerve after losing its medullary sheath divides more or less 

 dichotomously and spreads itself along the length of the muscle 

 fiber. The band variety is less common ; one notes that the 

 better stained the preparation the less frequently it appears. 



^ Arch. f. mikrosk. Anat., 1890, Bd. xxxv. 



