These young ones, as with other marsupials, spend a period of time inside the mother's "pouch" before venturing out into the world.
In the case of the koala, this pouch is located below and in back of the mother;
the small koalas can climb out directly from the pouch and onto the mother's back before learning to feed and fend for themselves.
With all other marsupials, the pouch is located in the front,
perhaps most famously with the kangaroo, where the "joey" can sometimes be seen popping its head out of its soft, warm pouch to survey the world about it safely.
1 With all other marsupials, the pouch is located in the front. 与所有其他有袋动物一样，袋位于前部。
很多情况下，with all+名词，with all表示让步意义，意为虽然..., 尽管...，但是本句按照让步理解逻辑是不通的。所以这里就不是with all结构，而是with介词短语，碰巧后接的名词被all修饰而已。牛津词典with释义之一，with意为including。例如：With all the lesson preparation I have to do I work 12 hours a day.
2 perhaps most famously with the kangaroo, 或许最著名的就是袋鼠。
这个with介词短语修饰副词最高级most famously，with在此的意思是in the case of.