[1] The carapace's frontal regions are granulate, and its lateral margins are convex.

[1] C. granulosus is most commonly found on stony or boulder beaches.

[2] The species occupies both the supralittoral fringe (a region above the level washed by all tides, but subject to flying spray) and the midlittoral region (above the level not uncovered by all tides).

[2] However, the species typically occupies the upper midlittoral region.

[2] C. granulosus sometimes scrapes out shallow depressions beneath stones,[2] and is most commonly found under boulders.