No. 3.] MUSCLES AND NERVES IN AMIA CALVA. 613 
given off at the point where the main nerve reaches the inner 
surface of the coronoid process of Meckel’s cartilage and is 
twisted inward and downward. It runs downward along the 
inner surface of the cartilage and along the inner surface of 
the articular in front of the cartilage, across the hind end of 
the surface of insertion of Aw’, to the lower edge of that 
muscle. There it crosses the anterior edge of ossicle ‘c,’ 
then turns inward between the articular and the lower hori- 
zontal part of Meckel’s cartilage, and, having reached the 
inner ventral angle of the cartilage, issues from the mandible 
between the articular and the lower edge of the splenial, lying 
immediately dorsal to and in contact with the r. mandibularis 
facialis externus. It then turns upward and backward and 
enters the thin fold of skin that extends from the inner, lower 
edge of the mandible to the outer edge of the geniohyoideus 
muscle, and which I have already described as the hyoideo- 
mandibular fold. Traversing this fold upward and backward it 
reaches the outer edge of the geniohyoideus near its origin 
from the ceratohyal, and there turns downward and forward 
along the outer surface of that muscle. It crosses the muscle, 
reaching its median edge opposite the base of the third or 
fourth branchiostegal ray, and passes under that ray onto the 
outer, ventral surface of the inferior division of the hyohyoideus. 
There it anastomoses completely with the r. hyoideus facialis, 
the two nerves running directly into each other and forming a 
complete circuit, so that it is impossible to tell where one ends 
and the other begins. One long branch, apparently belonging 
to the nerve gis, is sent forward along the outer surface of 
the superior division of the geniohyoideus ; it sends branches 
into that muscle, and runs directly into a terminal branch of 
nerve 7,g/i, described below, forming with it a complete circuit, 
similar to that formed by the main nerve and the r. hyoideus 
facialis. Numerous other smaller branches are sent from the 
united main nerves forward onto the outer surface of the supe- 
rior division of the geniohyoideus, and forward, medianward, 
and backward, internal to the branchiostegal rays onto the 
outer surface of the hyohyoideus, being distributed mainly to 
the inferior portion of that muscle. 
