484 ALLIS. [Vot. II. 
continues in about the middle line of the bone to its hind edge, 
and then passing through the strip of dermal tissue, lying be- 
tween the frontal and nasal, enters the frontal at about the 
middle of its anterior edge. It traverses this bone along its 
middle line for about half its length and then curves gradually 
outward until it reaches the lateral edge of the bone, where it 
meets and anastomoses with the infra-orbital canal, as already 
described. Leaving this canal immediately, it runs medianward 
and backward to the hind edge of the frontal, and then into the 
anterior and lateral part of the parietal, where it comes to the 
surface and ends. 
Trunk 1 of this line leaves the canal at its extreme anterior 
end, and, running forward and laterally, has two openings at 
the outer edge of the nasal, immediately behind the notch 
made in this bone for the passage of the anterior naris. Trunk 
2 leaves the canal exactly at the bend, and runs forward toward 
the anterior edge of the nasal, where it branches regularly, and 
has four openings on the surface of the bone, three single and 
one double. Trunk 3, given off near the middle of the bone, 
runs medianward and forward, and has eight single and six 
double openings arranged along the median edge of the bone. 
Trunk 4 is given off nearly opposite the posterior nasal aper- 
ture from that part of the canal lying in the dermal tissue 
between the nasal and frontal. It runs forward and outward, 
turning backward along the median edge of the nasal aper- 
ture, and anastomosing with trunk 6 infra-orbital, as already 
described. Trunk 5 is given off laterally at about one-third 
the length of the frontal, and trunk 6 medianward at about 
the middle of it: both are short and stout. No. § sends a 
long branch backward, overlapping the anterior branches of No. 
6, and another forward almost to the anterior edge of the 
frontal. In front of this last branch, and also in front of several 
of the smaller branches, there are deeply channelled lines in 
which the epidermal canals of the system are continued onward 
along the upper surface of the bone, partly imbedded in it, and 
extending in some cases into the strip of tissue in front of it, 
reaching even tothe hind edge of the posterior nasal aperture. 
System 5 has twenty single openings and eleven double or 
channelled ones, and system 6, thirty-three single and ten double 
or triple ones. Trunk 8 is a direct continuation backward of that 
