142 



THE DISSECTION OF PIG EMBRYOS 



lateral chorioid plexus. The dorso-lateral wall of the diencephalon thickens to 

 form the thalamus and the third ventricle is narrowed to a vertical slit. The 

 increased size of the cerebellum has been noted. Into the thin dorsal wall of the 

 myelencephalon grows the network of vessels which form the chorioid plexus of 



Epiphysis Thalamus 

 Mesencephalon 



Pedunculus cerebri 



Cerebellum 

 Chorioidal plexus ventricle 4 



Tela of ventricle 4 

 Myelencephalon 



Epiglottis- 



Esophagus - 

 Spinal cord 

 Trachea . 



Tela chorioidea 



Lai. chorioid plexus 



Corpus striatum 



Hypophysis 

 Lobus olfactorius 



— Turbinate anlage 

 Palate 



Aorta ; 



R. atrium — 



R. bronchus 



Dorsal aorta 



Inf. vena cava 



Stomach — 



Pancreas _ 



Suprarenal gland ■ 



Pulmonary artery 



Genital 



Duodenum 



>nros 

 Colon 

 L. mesonephric duct 



Ureter 

 Urogenital sinus with mesonephric duct 



Gall bladder 

 Small intestine 



Urethra 



Bladder 

 Anus 



Rectum 

 Fig. 147. — Median sagittal dissection of a 35 mm. embryo. X 4. 



the fourth ventricle, which is now spread out laterally and flattened dorso-ven- 

 trally. About the notochord mesenchymal anlages which form the centra of the 

 vertebrcB are prominent. 



Turning to the alimentary tract, observe that the primitive mouth cavity 



