HamAkKeER. — Nervous Syst. Nereis, 
PLATE 3. 
Fig. 20. Parasagittal section of the cephalic segment tangent to the lateral surface 
of the posterior eye, to show the ciliated groove. 
Fig. 21. Enlarged view of part of Figure 24, to show the arrangement of the 
nuclei of the “mushroom body.” 
Figs. 22 and 23. Para-sagittal sections of fibre A (compare Fig. 27), showing 
relation to fibres B, and also contact of fibres B with each other. 
The median giant fibre also appears in Fig. 23. 
Fig. 24. Transverse section through the anterior part of the brain, showing the 
“mushroom body.” 
Fig. 25 is omitted. 
Fig. 26. Frontal section of a longitudinal connective. 
