u '^^' ^^, median longitudinal, or sagittal section through a rabbit em- 

 bryo, at the end of the twelfth day. The section is a strictly median one 

 except m two respects , the cerebral hemisphere of the left side has been 

 introduced m order to render the figure more complete ; and the Wolffian 

 body and ureter of the right side. The terminal portion of the tail has 

 been removed. 



BF, Cavity of fore-brain or tbalamencephalon. 



BH, Cavity of hind brain, or fourth ventricle. BL, Cerebellum 



BM, Cavity of mid-brain. BS, Cavity of cerebral hemisphere ' or 



lateral ventricle. CH, Notochord. GP, Post-anal crnt 

 IN, Finger-like process of iufundibulum. KC, Wolffian duct 

 KD, Ureter. KM, Wolffian bodv. LE, Epiglottis 

 LG, Lung. LR, Trachea. PN, Pineal body. PT, Pituitary body 

 Rb, Sinus venosus. RT, Truncus arteriosus 



^^'Z^'"'^'^'^^''"^^''''''^- T, Glottis. TA, Stalk of allantois, cut short. 

 TC, Cloaca. TA, Thyroid body. TO, (Esophagus. TP Pharynx 

 W, Liver. WD, Bile duct. YK, Yolk stalk, cut short. 



(Marshall). 



