498 ERNEST W. L. HOLT, 



Plate XXX, Figs. 10—17. 



Fig. 10. Section similar to 9, but somewhat oblique : showing anterior 

 commissure (c. a.) and pineal body (pw.). Z. A, Oc. 4. Cam. Luc. 



Fig. 11. Oblique horizontal section of the same, showing superior com- 

 missure {c. s.) passing from optic thalami {to.). Z. A, Oc. 4. 

 Cam. Luc. 



Fig. 1 2. Vertical transverse section taken through anterior part of optic 

 ventricle of |- inch herring, showing septixm (s.) and labium invagi- 

 natum or fibrous tract {t.f.) bridging over third ventricle. 



Figs. 13 and 14. Sections behind 12: showing disappearance of septum. 



Fig. 15. A similar section through bases of olfactory lobes of |- inch 

 herring , showing commissure (c ol.) uniting them. Z. A, Oc. 4. 

 Cam. Luc. 



Fig. 16. A similar section taken through mid-brain and infundibulum, 

 showing passage of fibres (/?.) from cerebral mass to tectum. Z. A, 

 Oc. 4. Cam. Luc. 



Fig. 16 a. A similar section taken further back, showing valvula {f. g.) 

 and pituitary body (pt). Beck ^ inch. Cam. Luc. 



Fig. 17. A similar section through mid-brain of -g- inch herring, showing 

 fourth ventricle (v. 4.) and cruciform commissure (c. cr.) of auditory 

 region. Z. A, Oc. 4. Cam. Luc. 



Plate XXXI, Figs. 18—22. 



Fig. 18. Vertical longitudinal section of brain of 1^ inch herring, 



showing olfactory lobes (I. ol.) and commissural bands of cerebellum 



(c. aq. and c. c). Beck J inch. Hartnack Prism. 

 Fig. 19. Pineal region of last. Z. A, Oc. 4. Cam. Luc. showing labium 



invaginatum {t.f.\ infrapineal recess (r.i.p.), velum infrapineale (/".) 



and superior commissure (c. S.). 

 Fig. 20. A similar section of ^ inch herring, rather lateral, showing 



commencement of velum infrapineale (f.). Z. D, Oc. 4. Cam. Luc. 

 Fig. 21. A similar section of larval Zoarces viviparus, about 1^ inch : 



showing double nature of superior commissure (c. S.). 

 Fig. 22. A similar section across the brain of an early post -larval 



Zoarces viviparus. 



