GENERAL DIRECT 10 \ OF DEVELOPMENT. 



1015 



FROM A TO N IS A SERIES OF UIAGRAMMATIC FIGURES SHOWING THE MANNER IN WHICH THB 

 EMBRYO AND ITS ENVELOPES ARE FORMED. 



t)«. Vitelline membrane; e, embryo; pp, pleuro-peritoneal cavity; af, folds of the amnion; a. 



mj^Tr"' "'f ,f' '*'"*^ containing the liquor amnii ; dl, aliantois ; a' digestive tube; f 

 or ys, Titeiius, or vitellin sac. > & » » 



