It had the power of rolling itself up nearly double; in the same manner as a wood-louse, but not quite so close; eyes distinct and prominent.

It lived a long time out of water, and appeared to me exactly like an animal I caught on the 21st November 1837, in south latitude 24 degrees 19 minutes; east longitude 107 degrees 8 minutes.
We also this day caught a Janthina.

They have a little valve for the purpose of taking in air, with which to expand their float.

These animals go in company.

They emit when touched a brilliant scarlet dye.