254 PROCEEDINGS OF THE CANADIAN INSTITUTE. 
the nucleus visible, being left behind in the basal part of the cell 
surrounded by a scanty amount of apparently unaltered protoplasm. 
(f) Clavate Cells.—These gigantic cells, first described by Leydig 
as ‘ Kolbenzellen, enter very largely into the formation of the epi- 
dermis in Amiwrws, as indeed into that of many fresh-water fishes, 
such as the eel, burbot, and tench. They have also been examined 
with care by Pfitzner in the skin of salamander larve, and are de- 
signated by him ‘ Leydigsche Schleimzellen.’ 
It is with some difficulty that one succeeds in getting ‘ clavate’ 
cells (as they may be termed) isolated. After twenty-four hours in 
Miiller’s fluid the other epithelial cells fall readily asunder, but the 
clavate cells are generally surrounded by a sort of capsule formed 
of the neighbouring ordinary epidermal cells. These may be in time 
brushed off, but they invariably leave their trace upon the outer 
surface of the wall of the clavate cell in the form of a reticular 
sculpture. When freed from the adherent cells the clavate cells of 
Amiurus ave found to vary considerably in their form; the smaller 
ones are rounded or oval, and this is the case also in young fish, but 
in adults the proximal end tapers and frequently divides extending 
down towards the corium, but getting no nearer than the row of 
palisade cells between which the divided ends frequently dovetail. 
The clavate cell has a distinct wall, which, like the wall of other 
epidermal cells, is merely the outermost layer of the protoplasm, 
acquiring a certain amount of independence with the age of the cell. 
In small cells and in young forms I find the clavate cells filled with 
a granular substance which has a certain refractive aspect, and con- 
tains one large or two smaller nuclei in various stages of separation 
from each other. In preparations from adult skin the contents of 
the clavate cells are very different ; vacuolation has set in either at 
one or both ends of the cell, generally at the proximal end first, and 
the vacuoles which are occupied by a colourless fluid are separated 
by a network of protoplasm still in contact with the rest of the 
granular substance, Also in the neighbourhood of the nucleus does 
vacuolation take place, resulting.in a clear area through which only 
a few protoplasmic fibres straggle from the nucleus to the granular 
matter. Vacuolation proceeds till very little of the granular matter 
is left, but that generally assumes a somewhat crescentic outline at 
the broad end of the cell, forming a sort of cap—‘ Kappchen’—to 
the rest of the contents. By the time this process has advanced so 
