What feature of the human cecum is lacking in the fetal pig?

In frogs, yolks are plugged into the bottom of the blastopore, which develops into the anus. How about in sea urchins? I know in sea urchins the blastopore will become an anus but is there also a yolk plug, or does the bottom of the archentron simply develop into the anus?

Endodermal Derivatives of the 10 mm Pig Embryo   QUESTIONS (1) What is the double membrane separating the pharyngeal pouch and furrow? (2) What is the position of the first visceral arch in relation to the mesencephalon in your slide? (3) What is the fate of the postanal gut?

In a female fetal pig, what is the urogenital sinus?  Next, explain what changes take place with this structure as the fetus develops into an adult, describing how the exits for the excretory and reproductive systems change.