178 Journal of Comparative Neurology. 



In the frog, in many thin, flat, fascia-Hke tendons, into 

 which the muscle fibers are inserted, notably in the tendon of 

 the tibialis postiais from which many of our preparations were 

 taken, we have found numerous terminal arborizations of nerve 

 fibers. 



Often we have been able to trace medullated nerve fibers 

 for some distance, which, at each node of Ranvier, send off a 

 medullated branch, which passes out for a considerable but var- 

 iable distance from the parent trunk and then breaks up into a 

 a large number of fine non-medullated nerves, all extending in 

 the same general direction and sometimes branching again and 

 appearing as ordinary varicose fibers. The varicosities are all 

 round or oval in shape, vary but little in size and are connected 

 by very fine thread-like fibrillae. There are usually no side 

 branches and no projections along the course of the non-medul- 

 lated nerves, but the nerve fibers differ in length and the whole 

 tuft looks not unhke a small tree-like bush with long, slender 

 nearly parallel branches, tapering toward the top, on which the 

 buds are somewhat swollen, but which are unadorned with flow- 

 ers, fruit or foliage. 



Occasionally at the end of some of the terminal branches, 

 may be seen a round or oval enlargement somewhat larger than 

 the varicosities found along the non-medullated fiber. At other 

 times, the fiber seems to stop quite abruptly as if it were broken 

 off, or it may terminate in a sharp point. This description of 

 terminal nerve tufts applies equally well to all the plaques seen 

 in the frog. Whatever variation is seen in the ending is due 

 therefore to the arrangement of these plaques and their relation 

 to each other and to the medullated nerve. At times, the 

 medullated nerve divides into two main branches at right angles 

 to the stem, each of which quickly breaks up into a tuft similar 

 to the one just described. The whole appearance is then not 

 unlike what might be presented were two such bushes as above 

 described, cut off just below the point of branching and placed 

 base to base. Occasionally we see a tuft from one nerve fiber 

 extending out and meeting one from another nerve fiber, the 

 whole forming a spindle-shaped ending with medullated fibers 



