That is a fetus brought to term, between an embryo and a fetus there is a lot of conceptual space. This premature fetuses are basically fully formed creatures b

That is a fetus brought to term, between an embryo and a fetus there is a lot of conceptual space. This premature fetuses are basically fully formed creatures but small, we have no idea how to do the first part. Also again: we're doing this looking at a working plan, it's different from guessing how one for an extinct animal may look like.