340 



vertebrates where this is localized. See Figs. 1 and 2. In cross- 

 sections of the recti muscles of the rabbit, double - stained as above 

 indicated, no Doyere's elevations are found at places where the sen- 

 sory fibres would seem to terminate in or on the muscle fibres. The 

 anterior portion of the recti muscle were used for cross -sections. In 

 this region I have never found the motor endings. 



Cross- sections further show that the endings in question are not 

 under the sarcolemma, as are the motor endings, but are found in 

 the connective tissue surrounding the muscle fibres. In Fig. 3 are 

 reproduced four cross-cut muscle fibres by the side of which the sen- 

 sory endings may be seen; these are beyond a reasonable doubt out- 

 side of sarcolemma of the muscle fibres reproduced. In many in- 

 stances, however, the relation of sensory endings to the sarcolemma 

 can not be clearly made out. In muscle fibres cut slightly obliquely, 

 I have found it often quite impossible to tell, even when the section 

 was viewed under the */i2 i n - °ü immersion, whether the ending was 

 on or under the sarcolemma. In Fig. 3 are reproduced some of the 

 clearest examples of the extrasarcolemmic termination of these sen- 

 sory endings, I have found in a large number of preparations studied. 

 The fact that these endings arc 1 outside of the sarcolemma, while all 

 the motor endings in striated muscle tissue, with which I am familiar 

 are under this membrane, would seem to me sufficient reason for con- 

 sidering them other than atypical motor endings. In this account of 

 the termination of the sensory fibres, special consideration has been 

 given to the endings of the lateral branches to which reference has 

 been made above. The termination of the nonmedullated continuation 

 of the medullated sensory fibres may now be considered. These have 

 been correctly described by Retzius and I can do not better than use 

 his own words in drawing attention to them: — 



"Von besonderem Interesse sind indessen die schon oben kurz 

 erwähnten Endverästelungen , welche weit in die Länge gezogen sind. 

 Entweder verläuft die Faser, welche oft einen Seitenzweig einer mark- 

 haltigen Nervenfaser darstellt, unverästelt längs der Muskelfaser, oder 

 auch teilt sie sich dichotomisch in zwei Aeste, welche längs der Muskel- 

 faser in entgegengesetzten Richtungen ziehen, wobei sie sich noch 

 weiter verästeln können. Solche Aeste ziehen zuweilen eine weite 

 Strecke, bevor sie frei endigen. Während des Verlaufs sind sie hier 

 und da mit Endscheiben versehen, welche eine verschiedene, bald 

 rundlich - ovale , bald dreieckige, bald wurstförmige Gestalt haben". 

 One such terminal ending, a relatively short one, however, is shown 



