GANGLIA AND NERVES OF SQUALUS 25 
Neal (’98, p. 233) has discussed the relation of the various 
divisions of the portio minor and my results agree substan- 
tially with his rather than with those of Mitrophanow, ’93. The 
mode of entrance of the profundus root in Lepidosteus (Land- 
acre, 12) reinforces the identification of the most anterior root 
as that of the profundus since in Lepidosteus the root of the 
profundus enters well forward and entirely distinct from that 
of the Gasserian. There can be little doubt in my opinion that 
the second root is visceral motor. In Neal’s paper he does not 
describe three roots in detail but figures them (Neal, ’98, p. 234, 
fig. K.). 
From the anterior end of the ganglion in the specimen plotted 
extends a mass of cells from which no fibers pass out, the ramus 
ophthalmicus profundus leaving the ganglion near its mid-ven- 
tral border. This forward extension of the ganglion is evidently 
the remains of the structure which Neal identifies as a persistent 
connection of the ganglion with the ectoderm (Neal, ’98, p. 
234, fig. K.) and which Scammon (’11, pp. 54, 55, figs. 11 and 
12) identifies as the utrochlea process, i.e., the remains of the 
connection of this ganglion with the neural crest. This process 
gives the profundus ganglion a curious shape in contrast with 
nearly all other ganglia, in which the nerves practically always 
arise from the free end of the ganglion. In this case, as men- 
tioned above, the profundus nerve arises near the mid-ventral 
border of the ganglion. The proximal portion of the profundus 
wnerve is difficult to follow in the 22 mm. embryo on account of 
its being compressed between the mesial wall of the orbit and 
the primordia of the eye muscles and adjacent blood vessels. 
After it reaches a point at the level of the dorsal border of the 
lens its course 1s easily followed. It forms a gentle curve ceph- 
alad and ventral, more than half of its course being mesial to 
the eye. In a 30 mm. specimen the whole course of the nerve 
is well isolated. 
The profundus nerve, aside from its large size and length as 
compared with the r. oph. sup. V, has the relation usual in elas- 
mobranchs and ganoids. Only two small twigs (figs. 1, Pro. 1, 
Pro. 2) seem to be given off before the nerve reaches its most 
