The spotted salamander embryos continue to grow. They started as undifferentiated balls. They were probably laid on March 14, 2015, so this photo is 2 days after conception.
Pistachio stage. This seems to be called “neutralization” but that is up to debate. At four days on March 18, the embryos have developed a top and a bottom. The bulbous end will be the head.
Starting to look sluggy. At 7 days, these salamanders definitely have a top and bottom and look like some kine animal. They are also very hard to photograph through egg goo.
Ten days old, and definitely slugs. The tail end is sort of pointy, and the head end is becoming flat. They are maybe three millimeters long. They can hatch at thirty days, depending on conditions, so could be a third of the way along.