A New Count of Allantoic Cells of the 10-Day Chick Embryo

Abstract

The mean number of allantoic cells/square Cm. of the allantoic membrane in 10-day chick embryos was estimated by direct counting with the phase contrast microscope. In the chorionic (CA) portion of the allantoic membrane there were 1.66 x 105, and in the amnion-yolk sac (AYA) portion 3.00 x 105 allantoic cells/cm2. The total area of the allantoic membrane was measured directly. The area of the CA portion was 57.9 cm2, that of AYA portion was 29.1 cm2. The number of cells lining the allantoic cavity of the 10-day chick embryo was estimated to be 1.8 x 107.