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from ventricular to ectal surface. Each cell has its nucleus and the 
neuroblasts arise between them near the ventricular surface. During 
the development of the nervous matter these cells suffer great modi- 
fication. The ganglion cells migrate peripherad forming a dense inner 
zone and a less dense peripheral zone. The walls of the original 
epithelium collapse in passing through the cellular layer and become 
very much confused (fig. 6). Fusarı has been misled by this appea- 
Fig. 5. A portion of a longitudinal section of the tectum of Trutta fario, 9 
days old, showing the horizontally placed optic tract cells and the connection of the inner 
cell layer with the lemniscus fibres. 
Fig. 6. Basal (ventricular) portion of the tectum with two of the ganglion cells 
of the so-called granular layer. 
Fig. 7. A portion of the dorsal ventricular surface of the axial cerebral lobe of 
Amiurus showing the connection of the epithelium (ependyma) cells with the fibrous 
framework and also the oblique position of the ventricular cells while the deeper cells 
connect directly with the axis cylinders of the peduncles. 
