476 ALLIS. [Vou. II. 
The anastomosis of these two peripheral systems is not formed 
until the fish is well advanced in age. In the large 15-month 
specimen shown in Fig. 17, it is just forming. It is brought 
about in the following way: trunk 4 supra-orbital, which leaves 
its canal immediately in front of the frontal, runs forward and 
laterally until it reaches a point median to the anterior edge 
of the posterior nasal aperture. Here it turns backward, and 
runs toward the anterior edge of the frontal, often extending 
beyond this edge onto the upper surface of the bone. Trunk 6, 
infra-orbital, lies almost exactly in the line of the main part of 
trunk 4, supra-orbital, the two trunks and their system of pores 
and branches growing directly toward each other until either 
the trunks or some of their branches come squarely together 
and unite at or near the bend in trunk 4, enlargements being 
usually formed at the points of union. A remnant of the divid- 
ing wall remains, indicating the line where the two systems 
came together. Zzzs zs the only place in the entire lateral system 
of Amia where an anastomosts below the surface occurs; for, even 
where terminal branches of the same or neighboring systems are 
united below the surface, as shown in Fig. 4o, Pl. XL., z%, the 
union, so far as I have been able to determine, is always first 
formed at the surface by the fusion of two pores in a manner to 
be fully described in treating of the development of the system. 
Leaving the antorbital at its hind edge, at about two-thirds 
the length of the bone, the main canal enters the upper anterior 
edge of the lachrymal, and, running backward along its middle 
line, gives off the trunks of three peripheral systems, — trunk 
7, immediately on entering the bone, trunk 8, about half-way 
through it, and trunk 9, just before leaving it. All these trunks 
run outward, downward, and forward. Trunk 7, which is short, 
lies just above a small notch in the lower anterior corner of the 
lachrymal. Its system has three large openings along the upper 
edge of the notch, and five along a slender branch directed 
backward from it, making eight in all. 
The openings of the next two systems, 8 and 9, are arranged 
along the entire lower, lateral edge of the lachrymal. No. 8 
has three double and two single openings, and No. 9 two double 
and seven single ones. One of the double openings in this last 
system is formed by the anastomosis of two branches at their 
outer ends, an instance of the fusion of two pores in adult life 
