676 ANATOMY OF THE MUZZLE OF ORNITHORHYSCIIUS, 



penetrate the outer fibrous sheath, entering amongst the epithelial 

 cells forming the follicle, where their axis-cylinders suddenly 

 expand into vesicle-like swellings, as seen in specimens stained 

 with logwood and carmine (figs. 2, 5). The swelling of the axis- 

 C3'linder, as seen in such specimens, is faintly granular and exhibits 

 a knotted appearance. This is seen in specimens stained by 

 Kultschitzki's method* to be surrounded by a thin expansion of 

 the medullated sheath, outside which again is a sharply defined 

 nucleated capsule, continuous with the primitive sheath of the 

 nerve fibi'e (figs. 2, 5, n). 



Fresh tissue impregnated with gold chloride ])y Ranvier's 

 method, or bichromate-hai'dened tissue stained by Freud's gold 

 method give ample demonstration of the connections of these 

 swellings with the axis-cylinders of the nerves (fig. 7). 



We thought it possible that Golgi's silver impregnation method 

 might show the existence of further ramifications, such as we had 

 found to occur among the epithelial cells of the rod organs, but 

 though by this method the end-swellings stained and their connec- 

 tion with the axis-cylinders was well shown, no trace of any 

 further prolongation was to be seen. This negative result seems 

 fairly conclusive, as the intra-epithelial ramifications of axis- 

 cylinder branches were well impregnated in neighbouring push- 

 rods. By no method of staining is there shown the slightest 

 indication of nucleus in the end-swellings, although the nucleus 

 of the capsule surrounding it, when viewed from the surface, 

 might in some instances be mistaken for one. 



Poulton's figs. 8 and 12 showing these bodies as definite 

 nucleated ganglion cells are, thei-efore, quite erroneous and mis- 

 leading, t 



In addition to the nerve-terminations described above, Golgi 

 preparations show leashes of fibres running upwards tuwards the 



t Occasionally the optical transverse section of the axis cylinder before it 

 swells out into the enlarged knob, gives rise to an appearance somewhat 

 simulating a nucleus. 



* Anat. Anzeiger, ISSH, p. 223, and Zeitschr. f. vviss. Mikros. vi. 2, 1889, 

 p. 196. 



