A genus of transparent, tubular, free-swimming oceanic tunicates found abundantly in all the warmer latitudes. See Illustration
in Appendix. [1913 Webster
" Each species exists in two distinct forms, one of which lives solitary, and produces, by budding from an internal organ, a series of the other kind. These are united together, side by side, so as to form a chain, or cluster, often of large size. Each of the individuals composing the chain carries a single egg, which develops into the solitary kind."