318 JAMES EDWARD ACKERT 



outer root sheath of a common hair on the face of Vesperugo 

 serotinus. 



According to the observations of Sabussow ('10) the hair of 

 the flying membrane of bats is supphed with several meduUated 

 nerve fibers whose number is never less than two. These fibers 

 approach the hair follicle, divide, spread around the hair spirally, 

 more or less in the form of a ring, give off small fibrils from the 

 latter, branch, and finally end in the form of a 'pahsade' on the 

 hyaline membrane. The fibrils of the 'palisade' may contain 

 varicosities along their courses, or their distal ends may be lance- 

 shaped. The spiral ring around the 'palisade' consists of small 

 varicose threads. This Sabussow holds as a second kind of 

 nerve ending on the hair. He asserts that he never saw these 

 two kinds of endings, namely, the 'palisade' and the varicose 

 threads of the spiral ring, at the same time in the same hair. 

 From this he concludes that there exist two kinds of hairs, each 

 of which is supplied with one of these nerve terminations. 



Parallel with the spiral ring just described and more super- 

 ficial, Sabussow observed a broadly meshed network of fibers 

 resembling a nerve ring, and apparently surrounding the hair 

 above the sebaceous glands. This network or ring, which be- 

 longs to the second nerve layer, could by focusing be seen to give 

 off more or less flattened fibers resembling the 'palisade.' Being 

 unable to find any definite connection between the 'palisade' 

 apparatus first described and this one which comes from the 

 subepithelial network, Sabussow inferred that the two were 

 independent. 



In the writer's deeply stained methylene blue preparations 

 of the bat's skin, both of the body and of the membranes, the 

 hair follicles with their numerous nerves stand out in bold contrast 

 to the surrounding, weakly stained connective tissue (figs. 8, 9). 

 The nerves which supply the hairs arise from the second nerve 

 layer, pass outward to approximately the level of the inner third 

 of the hair follicle, where, at first, they appear to pass along from 

 one hair to another. But upon close examination it is seen that 

 nerves may be distributed in one of two ways: (a) The whole 

 fiber may end directly in a single follicle (figs. 8, 9, ff) ; (b) Upon 



