INNERVATION OF INTEGUMENT OF CHIROPTERA 313 



NERVE ENDINGS IN THE INTEGUMENT 



The nerve terminations in the integument of Chiroptera may 

 be grouped into five classes as follows: 



1. Free nerve terminations in the epidermis 



2. Nerve endings on hairs 



3. Special sensory end-organs 



a. End-bulbs 



b. Terminal corpuscles 



4. Motor nerve endings on striated muscles 



5. Nerve endings on modified sweat glands 



1. Free nerve terminations in the epidermis 



As was stated in an earlier part of this paper (p. 308), free nerve 

 endings in the form of minute swellings were observed in the strat- 

 um Malpighii. These free nerve terminations or end-knobs can 

 most readily be seen in sections of the ventral portions of the 

 membranes, where little or no pigment is present. Especially 

 desirable for this purpose are oblique sections, or those which 

 contain small areas of the surface of the membrane (fig. 6). In 

 such sections it is possible to focus down through the trans- 

 parent stratum corneum, thereby obtaining distinct views of the 

 deeply stained (blue) nerves of the third layer (fig. 6, n). The 

 latter stand out in bold contrast to the weakly stained cytoplasm 

 of the Malpighian stratum. In sections 20/x thick one can, b}^ 

 focusing, trace non-medullated nerve fibers, from the point of 

 branching near the surface of the corium, on out among the 

 deeper Malpighian cells. The larger fibrils and the smaller ones 

 given off from them are plainly visible. Finally, among the 

 cells of the stratum granulosvmi (fig. 6, sgr), the ultimate branches 

 terminate in minute round or oval end-knobs (figs. 6, 7, e). 

 Similar structures were mentioned but misinterpreted by Schobl, 

 who, observing a very limited, number of minute round swellings 

 resembling fine nerve endings in the stratum Malpighii con- 

 cluded that they were foreign particles due to faulty technique. 



The end-knobs take a deep blue stain similar to that of ordi- 

 nary axis cylinders, and appear to be homogeneous in structure. 

 They are oval or spherical, their size varies from 0.5/x in length 



