PLATE 6 



EXPLANATION OF FIGURES 



37 A medial sagittal section of a larva, Stage IX. X 75. 



38 Same, Stage X. X 75. 



39 Same, Stage XI. X 75. 



40 A medial sagittal section of a 38 mm. adult. X 47. 



41 Transsection through the habenulae and posterior part of the telenceph- 

 alon, 13 mm. larva. X 75. 



REFERENCES 



a. c, anterior commissure 

 arch., archenteron 



b. v., blood vessel 



cbl. c, cerebellar commissure 

 ch., optic chiasma 

 di. pL, diencephalic plexus 

 ep., epiphysis 



ep. a., anterior evagination of epiphysis 

 ep. p., posterior evagination of epiphy- 

 sis 

 hip. c, hippocampal commissure 

 hyp., hypophysis 



TO. cbl.f., mesencephalic-cerebellar fold 

 vies, p., mesencephalic pit 

 77) j)J., metaplexus 



7ich., notochord 

 par., paraphysis 



par a., anterior paraphysial evagination 

 par. p., posterior paraphysial evagi- 

 nation 

 p. c, posterior commissure 

 p. hip., primordium hippocampi 

 pr. en., pre-oral entoderm 

 p. V. a., post-velar arch 

 s. c, superior commissure 

 St., striatum 



tcl. ph. telencephalic plexus 

 /. p., tuberculum posterius 

 v. I., velum transversum 



