This specimen is relatively small. P. diogenes is the world’s second-largest hermit crab species, growing large enough to inhabit a full sized queen conch shell and beaten only by the terrestrial coconut crab, which is a hermit crab that stops using shells when it matures.
I can only assume that the the “diogenes” in its name comes from some parallel drawn between the hermit crab’s shell and the philosopher’s habit of sleeping in a large jar.