Tunicata

1. n. pl. A grand division of the animal kingdom, intermediate, in some respects, between the invertebrates and vertebrates, and by some writers united with the latter. They were formerly classed with acephalous mollusks. The body is usually covered with a firm external tunic, consisting in part of cellulose, and having two openings, one for the entrance and one for the exit of water. The pharynx is usually dilated in the form of a sac, pierced by several series of ciliated slits, and serves as a gill.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.