Sowpig

[…] he went in search of some sowpigs (woodlouse), and while doing this had the good fortune, in turning up a stone, to find the fly I had come after.

[…] sowpigs, all of which were in small stone enclosures. Moving about among the animals were Little Men who were dressed like farmers, but whether they were farmers or not he could not tell.

The hatchling sowpigs (Cornwall) that leave the maternal pouch are tiny, soft and pale but soon harden up.