Isn’t the English language wonderful in its ambiguity? It’s not the eggs that are carnivorous but the mollusc that laid these eggs. According to the good folks at the Queensland Museum, it’s a predatory marine snail and most likely to be one of the murex snail group (family Muricidae), possibly Lepsiella hanleyi or Morula marginalba (the mulberry whelk, photo further down), or even one of the cone snail family (Conidae), Conus papilliferus.
Egg cases under a rock in a rock pool
Here’s a shot showing real size.
Make sure you put rocks down in exactly the same position and place they came from
I’ve seen those cone shells, and Morula marginalba is prolific on that rock platform.
Two hermit crabs about to grapple - the one on the right is in a Morula marginalba shell.
The hermit crabs above are possibly Clibanarius virescens.
This website shows photos of a bunch of different mollusc egg masses.
