Normentafeln zur Entwicklungsgeschichte der Wirbeltiere. 



Stage 



Series 



Length 



lO 



II 



12 



13 



14 



16 



17 



18 



12 



18 



20 



25 



28 



35 



38 



40 



48 



55 



65 



69 



73 



>S5 



Age 



I day 4 hrs. 

 I day 8 hrs. 

 I day 12 hrs. 



1 day 16 hrs. 



2 days 2 hrs. 



2 days 7 hrs. 

 2 days 12 hrs. 



6 days 16 hrs. 

 10 days 16 hrs. 



13 da3's 3 hrs. 



14 days 4 hrs. 



14 days 19 hrs. 



15 days 10 hrs. 



16 days 



16 days 10 hrs. 



17 days 



17 days 17 hrs. 



iS days 15 hrs. 



Elastomeres 



Volk 



2 



6 



12 



20—24 

 80 — 100 



200—250 



500—600 



Lower portion six surface grooves. 



Lower portion nine surface grooves; 

 none reach center of egg. 



Lower portion twelve surface grooves ; 

 few reach center of egg. 



Lower surface as above excepting 

 several grooves reach center of egg. 



Lower portion forty surface grooves; 

 yolk much segmented. 



