Remember those Short-Tailed Opossum (Monodelphis domestica) neonates from last week? After some chemical treatments, the specimens were frozen into a cutting compound, and then sectioned into 300 micron (0.01 inch) thick slices on the cryostat. Here are three slices from the same animal. The sagittal sections (parallel to the midline that divides the body into right and left halves) show all sorts of wonderful details such as the chain of the vertebral column in white, developing bones of the skull, liver, gut, eye, and tongue. These sections look amazing, but they are not done yet! Come back to find out what happens next. Image credit: Curious Sengi.