Wilson, Motof Endings of the Frog. 13 



5, Fig. 3, Fig. 6.). Whether this is merely an interlacing or a 

 true anastomosis, it would be difficult to decide. The close 

 approximation of some of the terminals and the way in which 

 they run together (Fig. 6) suggest at least a very intimate re- 

 lationship between them. By means of this plexus arrange- 

 ment we can well understand how effective the nerve impulse 

 may become. From this network fibrillae may pass to other 

 muscle fibers (Fig. 3, Fig. 6). 



Not only in the fixed but in the unfixed preparations the 

 larger branches of the endings are seen to lie over the sarco- 

 lemma and even at some distance from it (Fig. i, Fig. 7). 

 In fresh preparations one occasionally sees a terminal lying over 

 the paler stained yet clearly outlined muscle fiber, and sending 

 down root-like structures to the muscle fiber. The neurone 

 enters into intimate relationship with the muscle fiber either at 

 the peripheral termination of the ending, where each termina- 

 tion appears as a very fine fibrilla to which an end knob or bulb 

 may be attached (Fig. i , B & C, Fig. 9) or at the terminal knob of 

 each of those root-like structures which at times are projected 

 from the fibrils of a nerve ending. The former termination, in- 

 cluding both the terminal fibrilla and its knob, lies in homogene- 

 ous substance under the sarcolemma ; it is covered by a cap into 

 whose formation there enters both the nerve sheath and the 

 sarcolemma, though chiefly the nerve sheath. The latter ter- 

 mination is in close opposition to the sarcolemma and may be 

 either in or under it. 



BIBLIOGRAPHY. 



Apathy, St. v. 



Kontraktile und leitende Primitivfibrillen. Mitteil. d. zool. Stat, zu Nea- 



pel, 1S92, Bd. 10, 355-375- 

 Das leitende Element in den Muskelfasern von Ascaris, Arch. f. 



tnikr. Anat., 1904, Bd. 43, p. 886-911. 

 Das leitende Element des Nervensystems und seine topographischen 



Beziehungen zu den Zellen. Mitteil. d. zool. Stat, zu Neapel, 1897, 



Bd. 12, p. 495-748. 

 Ueber Neurofibrillen. Proc. of the inter, cong. of zool., Cambr., 1898, 



Sep. 



