Normal Chorioallantois.

Normal Chorioallantois.
Intact fetal membranes surrounding a 3-to 4-month old fetus. The linear arrangement of the cotyledons reflects the linear arrangement of the caruncles in the endometrium. On average there are four rows of 15 cotyledons in each horn, i.e. 60 per horn, for a total of 120. The caruncles nearest the fetus are the larger ones.

Drost M (1978)