CFTAITEOTJS NEBTE-TERMrtTATIONS IN MAMMA.LS. 571 



cells of the epidermic lining of the hair-follicles both in feelers 

 and ordinary hairs ; and so far only does any question of their 

 homology with any nerve-element found in hairs come within the 

 scope of this inquiry. 



These fibres are alone represented in the noses of other classes 

 of the Insectivora, as, for example, in the Hedgehog, fig. 25, 

 Plate XVI. The causes and conditions of their existence in the 

 organ of Eimer are quite apart from those concerning the ex- 

 istence of the fibrils of the inner circle and of the centre group 

 there ; but these will be considered hereafter when we have 

 disposed of the question of homology between that organ and the 

 nerve-apparatus in hairs. The cause of the little swellings on 

 the course of intraepidermic nerves, wherever found, is as yet 

 obscure. Although apparently it is a modification of the fibril 

 due to the pressure or the presence of the epidermic cells there, 

 and sometimes due also to other conditions elsewhere, we must 

 be content with merely registering the fact, without pretending 

 to be able to account for it. The shape of these little bead-like 

 swellings difi'ers under conditions as obscure as their very exist- 

 ence : sometimes they are triangular in shape, as in the organ in 

 question, if, fig. 2, Plate XIII., or in the snout of the Hedgehog 

 (fig. 25, Plate XYI.) — sometimes globular and stalked, as in the 

 same organ ; and sometimes they are fusiform dilatations or beads, 

 as on the lower portions of the fibrils of the inner circle, both of 

 which are seen in figs. 1 and 2, Plate XIII. The presence of mois- 

 ture seems even to increase the size of these beads, as shown in 

 fig. 27, Plate XYI., from the mucous membrane of the palate in 

 the Mole. 



The Organ of Eimer a retrograded Sair-follicle. 



We have now arrived at the point where we may claim to 



establish a complete homology between the nerves composing 



tlie organ of Eimer and those nerves found upon an ordinary 



hair-follicle. To make this clearer, we place them in parallel 



columns. 



Hair-follicle. Organ of Eimer. 



Forked terminations. Fibrils of inner circle and Pacinian 



bodies. 

 Nerve-ganglion-cells. Nerve-cells at base of epidermic 



downgrowth. 

 Peripheral fibres of nerve-cells. Fibrils of tbe centre group. 



Nerves forming Jobert's coils. Subejiidermic plexus of non-medul- 



lated fibres. 

 Intraepidermic fibrils of follicle. Fibrils forming outer circle. 



MeduUated afferent nerves. MeduUated afferent nerves. 



