Determination of animal and vegetal pole
Do you have any reason to doubt this statement? The wikipedia article says pretty much the same thing. When reading the folllowing, don't forget that one can talk about such poles at different stages of development.


  The animal pole consists of small cells that divide rapidly, in contrast with the vegetal pole below it. In some cases, the animal pole is thought to differentiate into the later embryo itself, forming the three primary germ layers and participating in gastrulation. [..] The vegetal pole contains large yolky cells that divide very slowly, in contrast with the animal pole above it. [..] The animal hemisphere is dark brown, and the vegetal hemisphere is only weakly pigmented. 


and it comes with the following picture