The interhemal membrane of the bats, Rousettus leschenaulti and Cynopterussphinx (Megachiroptera): an ultrastructural investigation

Of the family Pteropodidae (Megachiroptera), only the placentae of Rousettu s and Pteropus have been examined ultrastructurally. Recently, the interhem al membrane characteristics of some members of this family have been questi oned. We report here on the fine structure of the interhemal membrane of Ro usettus leschenaulti and Cynopterus sphinx gangeticus. Contrary to earlier reports of a consistent endotheliochorial nature of the membrane until mid- gestation in Rousettus, such a condition is found to be restricted to the t rilaminar blastocyst stage. Thereafter, the placental membrane was hemodich orial. We also document how the trophoblast surface has been modified to cr eate honeycombed intrasyncytial desmosomes in Rousettus. The intrasyncytial lamina and maternal endothelium are lacking in the hemodichorial interhema l membrane of Cynopterus.