340 



THE MORPHOGENESIS OF THE CENTRAL NERVOUS SYSTEM 



anlage is at first flattened and soon is detached from its epitheKal stalk. Later, 

 it grows laterally and caudally about the anlage of the posterior lobe, and, during 



Diennphalon 

 Chorioid plexus 



Corpus striatum - 



Thalamus 



Pineal body (epilkalamus) 

 Cerebral peduncle 

 ' Cerebral aqueduct 

 -.' Mesencephalon 



Telencephalon/ \ ■'"'^-^^3feoi^ '^ \\- « % : ' ■^'^'^'""^ 



' "■ ' ~^'C€rrbdlum 



Metencephalon 

 Rhomboid fossa 

 Myelencephalon 



Opiu Hyp.i- "^ ■ 



ychia^ma pky^n Medulla 



Lamina lerminalis / uVp^/hala^s "'•'"'•i^""' 

 Rliincnccphalo)i 



Jr' - spinal cord 

 Central canal 

 Fig. 342. — Median sagittal section of the brain from a fetus of the third month (His in Sobotta). 



Pallium 



Foramen Monroi 



Third ventricle 



Optic vesicle- 

 Lens vesicle' 



Infundibulum' 



Rathke's pocket" 



Fig. 343.— Oblique transverse section through the diencephalon and telencephalon of a 10 mm. embryo. 



X 61. 



the second month, its wall is differentiated into convoluted tubules which obliter- 

 ate its cavity. The tubules become closed glandular follicles surrounded by a rich 

 network of blood vessels and produce an important internal secretion. Coinci- 



