196 Journal of Comparative Neurology. 



encircle the tendon bundles, thus realizing to a very limited ex- 

 tent the truth of Ciaccio's description " a anneaiix on a spirale." 

 Sometimes the non-medullated nerves run for some distance and 

 then widen out at the extremity into large, granular, flower-like 

 masses. As a rule, however, in the cat the terminal processes 

 are rather short and simple, compared with those of the rabbit 

 and dog and the enlargements rather small, often sessile or with 

 very short stems, and quite irregular, often leaf-like. The end- 

 ings are quite distinct, being rather small and well separated, 

 the one from the other. In the young kitten, a characteristic 

 end-organ from which is shown in Plate XVII, Fig. 24, the en- 

 tire ending is shorter and simpler. While the medullated nerve 

 branches quite as much as in the typical end-organ of the adult, 

 the terminal axis cylinders are short and but slightly branched, 

 often bearing at their extremities a single oval or pear-shaped 

 or clover-leaf granular enlargement, sometimes having a few 

 enlargements along their length, the larger ones enclasping the 

 tendon bundles and the whole spray twining slightly about the 

 fasciculus. The difference in complexity, then, which has been 

 mentioned, seems to depend entirely upon the difference in the 

 length and branching of the non-medullated fiber and the differ- 

 ence in number and size of the peculiar granular enlargements 

 which characterize this ending. 



In the rabbit, the form of neuro-tendinous end-organ, 

 which we have observed most frequently, is distinctly fusiform, 

 the nerve or nerves entering in the equatorial region and soon 

 branching into two or three or more secondary branches, ter- 

 minating by dividing into two or more non-medullated nerves, 

 which extend unbranched for considerable distances, bearing at 

 very short intervals enlargements of varied form and size, round, 

 oval, club-shaped, or very irregular masses, most of them 

 supported by a short pedicle. These are so closely packed 

 and so regularly placed about the fiber that the whole tuft has 

 a peculiar, long, cylindrical shape, but curves slightly in long, 

 sinuous lines, through the organ, while the side processes par- 

 tially encircle one or more of the small tendon bundles. This 

 form of terminal plaque is repeated with some variations at 



