Fig. 1. 
Fig. 2. 
Hamaker, — Nervous Syst. Nereis. 
PLATE 1, 
Diagram showing the disposition of the herves of the brain and sub- 
esophageal ganglion in dorsal aspect. In order to show the commissural 
ganglion and its nerves, the right anterior eye has not been indicated; 
I, V, a, B, y, nerves to the proboscis; II, nerve to the antenna; III, IV, 
VII, 6, e, É n, nerves to the muscles and the general surface of the head; 
0, commissure between the anterior and posterior cirrus ganglia; VI, 
nerve to the palp; VIII, IX, X, nerves from the brain to the commis- 
sural ganglion; XI, XI, optic nerves; XIII, nerve of the ciliated 
groove; XIV, three openings in the dorsal surface of the brain capsule, 
through which loose bundles of nerve fibres pass to the integument of 
the mid-dorsal region of the cephalic lobe. 
Para-sagittal section of a giant fibre to show the passage through it of a 
fibre of set B (compare Fig. 27). In this case the branching of the fibre 
B takes place within the giant fibre, and the axis cylinder of fibre B is 
shrunken. 
Cross section of a lateral giant fibre, to show the reticulum. 
Frontal section of the body wall between two parapodia, to show the rela- 
tive positions of nerves IV’, V’, and I’, and of the attachment of the 
longitudinal muscles and the dissepiment. 
Diagram of posterior aspect of part of a cross section, showing the dispo- 
sition of the parapodial nerves. The second and third parapodial nerves 
(compare Fig. 8) are designated by 2 and 8 respectively. 
Frontal section of a segmental ganglion, showing the intimate relation 
between the fibres of sets A and B (compare Fig. 27). 
Section similar to that in Fig. 6 showing the relation of the decussating 
parts of fibres B; also showing exceptional oblique course across the 
ganglion. 
Diagram showing the disposition of the segmental and parapodial nerves 
of a typical segment. J, II, III, IV, V, the five segmental nerves num- 
bered from in front backward. 1, 2, 3, 4, the four parapodial nerves. 
