arctisca

from The Century Dictionary.

• The water-bears, or bear-animalcules, otherwise known as the Tardigrada, Macrobiotida, or Colpoda, a group of uncertain value and position, formerly associated with the rotifers, but now usually considered an order of Arachnida, and located in the vicinity of the Acarida.

from the GNU version of the Collaborative International Dictionary of English.

• noun plural (Zoöl.) A group of Arachnida. See Illust. in Appendix.