Eutherian and Flying cat

Eutherian noun - Mammals having a placenta; all mammals except monotremes and marsupials.

Flying cat and eutherian are semantically related. In some cases you can replace phrase "Flying cat" with "Eutherian", this terms are similar.

Flying cat noun - Arboreal nocturnal mammal of southeast Asia and the Philippines resembling a lemur and having a fold of skin on each side from neck to tail that is used for long gliding leaps.

Eutherian and flying cat are semantically related. You can use "Eutherian" instead a noun phrase "Flying cat".