OBSERVATIONS ON THE CRANIAL NERVES OF SCYLLIUM. 489 
as such by Stannius,' Gegenbaur,” Jackson and Clarke,’ Balfour,* 
and others. Stannius’ points out that the buccal nerve in fishes 
is very variable; that it may either arise from the main stem of 
the fifth, from the maxillary or the mandibular, or from both 
these nerves, or, finally, may be absent altogether. 
Up to stage N, as shown in figures 6, 11, and 12, the buccal 
nerve is clearly a branch of the seventh, and could not possibly 
be taken for a branch of the fifth. After stage n, however, the 
connection between the roots of the fifth and seventh nerves 
becomes, as we have seen, very much more intimate; and at the 
stage between o and p, represented in fig. 14, the buccal nerve 
(vir d@), which is now situated completely in front of the maxillary 
(v 4), might very easily be taken for a branch of the fifth rather 
than of the seventh; careful examination shows, however, that 
the buccal, which is, as before, the most superficial of all the 
ventral branches, can be traced up to the dorsal root of the 
seventh from which it arises, as in the earlier stages. 
This origin of the buccal nerve from the root vita has 
already been noticed by Stannius,° who, however, as we have 
seen, did not refer the root in question to the seventh. Stan- 
nius’ figure of the nerve in Chimera’ shows clearly the very 
superficial position of the buccal nerve and its independence of 
both maxillary and mandibular nerves. 
Of the remaining branches of the seventh the anterior one 
(vir4) is shown im fig. 11 at its origin arising from a large 
ganglionic swelling on the main or hyoidean branch of the 
seventh, and running forward in close contact with the top of 
the spiracle (sp.), in front of which it divides almost at once 
into two branches, the distribution of which is shown in fig. 12; 
of these the anterior one (vit ya) runs downwards, forwards, and 
inwards, giving off numerous branches to the roof of the mouth. 
Im fig. 12 the anterior branches of this nerve appear to cross 
the posterior branches of the buccal, but it must be borne in 
mind that at this point the two nerves are at very different 
levels, the buccal beiug very superficial and the nerve (vit pa) 
lying very deep. This latter is seen in transverse section in 
fig. 7, which shows, on the right side, its origin from the 
ganglion, and, on the left, its distribution to the mucous mem- 
brane of the mouth. By comparing this figure with fig. 6, the 
1 Handbuch der Zootomie,’ p. 158. 
2 Loe. cit., p. 509. 
3 Loc. cit., p. 86. 
4 Op. cit., p. 195. 
5 *Das Peripherische Nervensystem,’ pp. 41 and 42. 
5 Loe. cit., p. 30. 
7 Loe. cit., Mal 1, fig. 1. 
