subplacenta
/ˌsʌbpləˈsɛntə/Zoology
noun
A structure located on the maternal side of the placenta; specifically that found in hystricomorph rodents, formed by the trophoblast, containing spaces filled with fetal blood, and possibly having a hormone-secreting function.
Origin
Early 19th century; earliest use found in William Lawrence (1783–1867), surgeon. From post-classical Latin subplacenta from classical Latin sub- + post-classical Latin placenta.