44 
MONICA TAYLOK. 
Stage 24. — Nerve-fibres have appeared in the peripheral 
parts of the brain and the spinal cord, and the roots of the 
fifth, seventh, eighth, ninth and tenth can be distinguished. 
Tliese roots are quite distinct one from the other. 
Stage 25. — The large roots of the fifth, seventh, eighth, 
ninth and tenth are conspicuous objects in sections, the fifth 
and seventh, in contra-distinction to their adult condition, 
being separated by a considerable interval. The optic and 
olfactory nerves are possessed of fibres. 
Stage 26. — The third nerve is developing. On account of 
the cranial flexure this nerve appears before the optic nerve 
in transverse sections. 
Stage 28. — The fourth nerve can be traced from the junc- 
tion of the optic lobes with the rhombencephalon. The 
acustico-lateral ganglionic elements of the seventh nerve 
can be easily distinguished from the Gasserian ganglion 
in these early stages and the lateral line root is widely 
separated from the vagus root. Even in the adult these two 
roots are separate, the lateral line branch transversing part 
of the floor of the auditory capsule in order to reach the 
vagus ganglion. 
The three main branches of the fifth can be traced to their 
respective destinations in Stage 28 and the hyomandibular 
branch of the seventh is conspicuous. The rudiments of the 
pre- and post-trematic branches of the ninth and tenth 
nerves are distinguishable in sagittal sections, as well as the 
palatine branch of the ninth. 
Stage 30. — Gasserian and geniculate ganglia are becoming 
massed into one large ganglionic centre which lies outside 
the brain-capsule — the condition which obtains in the adult. 
The pre- and post-trematic branches have fibres. By Stage 
32 buccal and palatine branches of the seventh as well as 
ophthalmic can be traced. 
Spinal Nerves. 
Fibres can be detected in the spinal nerve-rudiments in 
Stage 24, although the nerve is mostly protoplasmic at this 
