Before the evolution of legs from fins, the axial skeleton—including the bones of the head, neck, back and ribs—was already going through changes that would eventually help our ancestors support their ...

Newborn mice and 18.5-dpc fetuses were skinned and eviscerated, fixed in 80% ethanol, dehydrated in 95% ethanol for 1 d and acetone for 3 d. We then stained skeletons in 10% acetic acid in ethanol ...