INNERVATION OF INTEGUMENT OF CHIROPTERA 325 



is possible that these organs are varicosities in which the fibers 

 beyond the enlargements fail to stain. But they are found 

 constantly in deeply colored preparations, and moreover, are 

 somewhat greater in size than those ordinarily occurring in the 

 course of a fiber. Arnstein ('76) described varicosities in the 

 outer root sheath of sinus hairs in bats, and Sabussow mentioned 

 the presence of these structures on the courses of nerves out- 

 side of the root sheaths, but it appears that terminal varicosities 

 external to the hair follicles have not previously been observed 

 in Chiroptera. 



4. Motor nerve endings on striated muscles 



Voluntary muscles in the integument of the face, especially 

 in the upper lips of bats, are well developed. In sections stained 

 intra vitam with methylene blue these muscles are ordinarily 

 deeply colored, the cross striations being of a slightly darker hue. 

 Under such conditions it is usually possible to make out only 

 the muscle fibers and their nuclei; but in regions somewhat re- 

 moved from the larger blood vessels, where the blue stain is weak, 

 one can see medullated nerve trunks among the muscle bundles. 

 Along the muscle fibers which are stained only sufficiently to see 

 their outline, it is possible to trace medullated nerve fibers (fig. 

 11, nv) which give off a small number of branches. The latter 

 in terminating, form motor end-plates (figs. 11, 12, mep) on the 

 muscle fibers. 



It is not the purpose of the writer to enter into a discussion 

 of the literature on this important subject, but merely to describe 

 his observations and to mention wherein they agree or disagree 

 with those of a few recent workers. For a review of the literature 

 on motor nerve endings see Boeke ('09), Dogiel ('06), Huber 

 and DeWitt ('97). 



As a rule, the medullated nerve fibers can be traced to the 

 border of the muscle fiber. x4.t or near the edge of the latter, the 

 medullation stops and the nerve fibers soon begin to separate 

 into their component fibrillae, and finally end in a more or less 

 regular end-net or arborization (figs. 11, 12, ea). This is in accord 



