The Collaborative International Dictionary of English v.0.48:

Zooecium \Zo*oe"ci*um\, n.; pl. Zooecia. [NL., fr. Gr. zw^,on
   an animal + ? house.] (Zool.)
   One of the cells or tubes which inclose the feeling zooids of
   Bryozoa. See Illust. of Sea Moss.
   [1913 Webster]