TACTILE CORPUSCLES OF WAGNER. 221 



muscle-fibre, in intimate relation with the muscle-protoplasm ; 

 whether it lies underneath or external to the sarcolemma is 

 unsettled. The end-plates are flattened and elliptical in form, 

 and are made up of terminal branches of the axis-cylinder 

 supported by a protoplasmic plate or " sole." The sole is a 

 mass of granular protoplasm containing a number of nuclei, 

 and forms a bed or basis for the terminal nerve-branches. 



The nerve-fibre concerned, on reaching the end-plate, loses 

 its medullary sheath, and its axis-cylinder divides into branches, 

 enlarged and club-shaped, which ramify in an arborescent 

 way over the end-plate, supported on or imbedded in the sole. 



FIG. 86. 



End-plate of striated muscle-fibre of a squirrel's tail (Galeotti and Levi). 



Tactile cells occur scattered about in the lower part of the 

 Malpighian layer of the epidermis, and have a tactile function. 

 Each of them consists of an oval nucleated cell with its lower 

 surface resting in a meniscus, a concavo-convex or saucer-shaped 

 expansion of the end of a terminal nerve-fibril. Terminals of 

 this type are sometimes called " simple tar-tile cells," in con- 

 tradistinction to " compound tactile cells " (corpuscles of 

 Merkel and of Grandry), not found in man, in which two 

 or more cells are together associated with terminal nerve- 

 plates. 



The cells of Langerham, stellate cells occasionally found in 

 the epidermis, are by some regarded as nerve-terminal cells, 

 by others as wandering leukocytes. 



Tactile corpuscles of Wagner (or Mdssner] : These are ellipti- 

 cal structures situated in some of the papillae of the corium of 



