366 
A. M. REESE 
a considerable layer of loose fibrous tissue in which one or more 
small nerve trunks (figs. 9, nv) may be seen. 
Fig. 17 represents a transection of the epithelium and under- 
lying nerves and connective tissue, from the floor of a canal of type 
1, through one of the regions of greatest modification. The 
stratified epithelium (e) rapidly thickens, as it approaches the 
middle line, and is suddenly changed into the mantle cells (ms), 
which are vertically arranged, fiber- or rod-like cells, in which 
nuclei can with difficulty be seen. These mantle cells are bent 
over towards the median line of the canal to almost inclose the 
conical mass of sense cells (sc). 
While the minute details of the sense cells could not be deter- 
mined, they are, apparently, of about the shape of the sensory 
cells seen in the taste buds of the mammalian tongue. Each cell 
has the form of a much-elongated cone, ending in a sensory hair 
or bristle. A group of these bristles is seen, in fig. 17, h, projecting 
freely between the edges of the mantle cells. Each cell contains 
a large, oval nucleus with a distinct nucleolus. Whether or not 
there are elongated supporting cells between these sensory cells 
could not be determined. At the base of the sensory cells is a 
mass of small, irregular cells (sp) which may correspond to sup- 
porting cells; they may send fine processes up between the sensory 
cells but no such processes could be seen. 
As has been said above this group of sensory and mantle cells 
is larger and more distinctly seen at intervals of one to two cen- 
timeters but it is not a sharply defined sense group, like a taste 
bud. It becomes gradually smaller as it is followed caudad or 
cephalad from the section represented in the figure, until it 
practically disappears; then it becomes gradually larger again. 
As might be expected in poorly fixed tissue the fine connections 
between the branches of the lateral nerve and the nerve cells 
could not be determined. 
The groove-like depression in the upper side of the sensory 
epithelium, into which the bristles extend, seems to be invariably 
present. 
The epithelium of the canals of type 2 is quite different from 
what has just been described. These canals, as is shown in figs. 
