310 JAMES EDWARD ACKERT 



states that in preparations in which the lowest cells of the Mal- 

 pighian stratum remain undisturbed on the corium, no free 

 endings of the finest non-medullated nerve fibrils are found, and 

 that fibrils passing further toward the surface between the cells 

 of the stratum granulosum, are never to be found either on the 

 surface of the preparation or in cross section. He pointed out, 

 however, that occasionally round or elliptical, swollen structures 

 resembling fine nerve endings are to be seen, but these almost 

 always prove to be nodal points of division of nerve fibrils. These 

 minute swellings occurred so seldom that Schobl attributed their 

 presence to faulty technique. 



Sabussow ('10), working on the innervation of the flying 

 membrane, did not wholly accept Schobl' s idea of the distribu- 

 tion of the nerves of this part of the body. This investigator 

 found large nerve trunks in the innermost stratum of the pata- 

 gium, but held that Schobl' s second nerve layer lay in the same 

 plane as the first, and consequently could not be said to exist as 

 a separate nerve layer. Concerning Schobl' s third nerve layer 

 Sabussow simply stated that it is not double. But this investi- 

 gator confirms the existence of the fourth nerve layer of Schobl, 

 adding that, no matter how the membrane be torn, this layer can 

 be seen to be double. He also confirms Schobl's fifth layer, 

 which is non-medullated and double; but instead of the few 

 'swellings' which Schobl observed, Sabussow found numerous 

 varicosities. The latter sums up the layers he found as follows: 

 (1) a simple layer including the first two layers of Schobl; (2) 

 a broadly meshed double network with triangular enlargements 

 in it ; (3) a network of varicose fibers also double. Consequently 

 according to Sabussow, there are five nerve layers in the patagium. 



In transverse sections of my own preparations of the flying 

 and interfemoral membranes there can readily be seen, here and 

 there, regions which are approximately twice as thick as that of 

 the remaining area of these membranes. It is in these thickened 

 regions that the chief arteries, veins, nerve trunks and frequently 

 the principal muscle bundles are found. These particular 

 regions contain, as will be shown, one more layer of nerves than 

 do the others. 



