CUTANEOrS NEEVE-TERMINATIONS IN MAMMALS. 567 



wear of the protected free surface, and consequently the intra- 

 epithelial fibrils are allowed to follow their normal direction of 

 growth, which is one paroJlel to the surface. The same fibrils 

 seen in fig. 17, if, Plate XIY., from an ordinary hair-follicle cut 

 longitudinally, are represented in a feeler cut transversely in 

 fig. 13. The direction of those fibrils, however, although appear- 

 ing perpendicular, is really parallel to the surface ; and we 

 were compelled to alter the focus of the instrument very consi- 

 derably in order to draw their outlines. By usiug, however, a 

 binocular microscope, it was seen that, after passing the first layer 

 of cells, the direction of the fibrils, which were clearly in con- 

 nexion with the terminal (?) ganglion-cells, was parallel to the 

 axis of the hair and of the free surface of the follicle. 



Having now briefly described the nerve-structures found upon 

 the hair-follicles, in the order in which we previously enu- 

 merated them, let us now proceed to consider how far such 

 structures are represented in the organ of Eimer on the snout 

 of the Mole, or, rather, to reverse the problem, and show that the 

 nerve-elements in the organ of Eimer are only the representatives 

 or remains of nerve-elements usually found in hairs. 



Structure of the Organ of Eimer in the Mole. 

 In order to understand the nerve-arrangements composing this 

 organ, we must examine specimens showing it both in transverse 

 and in perpendicular section. When examined in transverse 

 section, it appears as if formed of circular groups of non-medul- 

 lated nerve-fibrils, each group being about the same size and 

 having the same arrangement in its component elements, although 

 these elements may vary somewhat in numbers, as seen in fig. 2, 

 Plate XIII. Each circular group is only about half the size of a 

 hair follicle cut in transverse section ; and they are removed from 

 each other by a distance equal to about that of their diameter. 

 The fibrils belonging to each group may be divided as follows into 

 three groups : — 



1. An outer circle, containing from 15 to 20 fibrils; 



2. An inner circle, containing from 10 to 15 fibrils ; 



3. A central group, composed of from 1 to 3 fibrils. 



In7ter Circle of Fibrils. — When seen in perpendicular section, 

 it is the inner circle of fibrils which constitutes the most pro- 

 minent object of the group ; and they are seen to form a cylindrical 

 column, generally more or less constricted in the centre, as shown 

 in fig. 1, Plate XIII., although in rare instances the cylinder appears 



