MULLENIX: EIGHTH CRANIAL NERVE. 233 



12, 15 (Plate 3), 18, 19, 20 (Plate 4). In other cases they originate as 

 branches of coarse fibres (Figs. 18, 23, 25, Plate 4). In still other 

 cases, fibres fork at the bases of sense cells and the branches appear 

 to clasp the bases of the cells "as a bird's claw would clasp a ball" 

 (Figs. 15, Plate 3; 17, 20, 23, 26, 27, Plate 4). 



In the majority of instances these terminal fibres do not penetrate 

 far beyond the basal ends of the sense cells (Figs. 17, 19, 20, 23, 25, 27, 

 Plate 4). I have observed cases, however, where they extend nearly 

 to the peripheral ends of the sense cells, or, rarely, quite to the ends. 

 Figure 31 (Plate 5) represents a terminal fibre which passes beyond 

 the nucleus and middle point of the cell, on that surface of the cell 

 which is nearest the observer. Figure 26 (Plate 4) shows another 

 fibre which bifurcates at the base of a cell, one branch appearing to 

 terminate near its point of origin, and the other extending almost to 

 the external ends of the cells between which it lies. Of course there 

 is the possibility that the shortness of the first mentioned branch is due 

 to the real terminal part of the twig having been severed in sectioning. 

 In Figure 18 (Plate 4) are shown fibres some of which reach the ex- 

 ternal cuticula, a layer often found covering the peripheral ends of 

 the sense cells. 



Whether the fibre shown in Figure 31 (Plate 5) and the left-hand 

 branch of the one shown in Figure 24 (Plate 4) are superficial, or are 

 in reality intracellular, cannot, of course, be stated with certainty 

 for these preparations, but there is so much other evidence of the inter- 

 cellular position of the nerve fibres that I feel justified in regarding 

 these as superficial fibres which lie on the surface of the cell next the 

 observer, and not as fibres which penetrate the cells. Figure 37 

 (Plate 5) represents material which was badly shrunken by the action 

 of the fluids used in the process of preparation, so that there are con- 

 siderable spaces between the sense cells. In this case the free terminal 

 fibres unquestionably lie in the spaces between the cells. Sections 

 parallel to the surface of the epithelium furnish conclusive evidence 

 in the same direction, as will be shown in a subsequent paragraph. 



In most cases these intercellular branches are entirely blackened, 

 and it is not possible to make out their fibrillar structure. Figure 26 

 (Plate 4), however, shows a case in which the individual fibrillae could 

 be seen. I do not venture to state whether the fibrillae in this case are 

 merely intertangled, or are fused together to form a true net work. 

 Neither do I feel justified in stating whether the individual fibrillae 

 end free at the termination of the fibre, or turn back in a loop at the end, 

 making a closed system of neurofibrillae, as suggested by Kolmer. 



