下腹的

Some of the patients have no obvioussymptom of abdominal pain, they only behave off colour, insomnic, tired, and so on.

临床表现为反复发作部坠胀疼痛、腰骶部酸痛，劳累或性交后加重，伴疲乏无力，或伴有低热。

Many species have a pouch (marsupium), a fold of skin covering the nipples on the mother's lower belly, where the young continue their development.

许多品种都有一育儿袋（marsupium），是在母体盖住乳头皮袋，幼体在袋内继续发育。