No. 3.] MUSCLES AND NERVES IN AMIA CALVA. 535 
8. Review and Comparison. 
In Laemargus (No. 26) the profundus arises by a root which 
is fairly separate and distinct from the root of the trigeminus, 
but connected with it by several small communicating branches. 
In Raja (No. 26) the roots of the two nerves are more inti- 
mately connected. In both Laemargus and Raja, and in Tor- 
pedo also (No. 28), the ganglion of the profundus is apparently 
wholly separate from and unconnected with the trigeminus and 
its ganglion, for Ewart does not mention any communicating 
branches in any of those fishes. He, however, says, in 
another publication (No. 27), that in skates the profundus 
ganglion is frequently connected by a communicating branch 
with the Gasserian ganglion. In sharks other than Laemargus, 
Ewart, in his preliminary communication, does not state defi- 
nitely whether there is or is not a separate profundus ganglion; 
in his complete work, in a diagram indicating the distribution 
of the cranial nerves in selachians in general (No. 29, Fig. 2) 
he, however, shows an entirely separate ganglion and root. 
Beard says (No. 8, p. 570) that in sharks the ganglion (meso- 
cephalic) and its root are found distinct in early stages of 
development, but in later ones both become fused with the 
ganglion and root of the trigeminus. 
Ewart, in his preliminary publication, describes but one nerve 
arising from the profundus ganglion in Laemargus. It is the r. 
ophthalmicus profundus. From it a small branch passes out- 
ward above the rectus superior, in the place, therefore, where 
the portio ophthalmici profundi is found in Amia, and then, 
from the main nerve, two or three ciliary nerves, presumably 
the ciliares longi and ciliares brevi combined, arise and, running 
forward between the rectus superior and rectus externus, enter 
the eyeball. No ciliary ganglion is described, but delicate 
communicating fibres are said to pass from the inferior branch 
of the oculomotorius to the ciliary nerves. The main nerve 
is then said to bend inward between the obliquus superior and 
the rectus internus, and end in the cutaneous and subcutaneous 
tissues in the snout. In its forward course small branches are 
sent outward, in front of the eyeball, and others to the skin 
