120 HISTORY OF BRITISH ZOOPHYTES. 



Its head gracefully nodded (whence the appropriate specitic 

 appellation, nutans, given to it by Sars), bending the upper 

 part of its stem. It waved its long tentacula to and fro 

 at pleasure, but seemed to have no power in contracting 

 them. It could not by any means be regarded as an apa- 

 thetic animal, and its beauty excited the admiration of all 

 who saw it.''"' — E. Forbes and J. Goodsir. 



Tribe 2. SERTULARINA. 



Family SERTULARIAD^. 



Character. Polypidoms plant-like, horny, rooted, variously 

 branched, tubular, filled with a semifluid organic pulp. Polypes 

 contained within sessile cells, which are variously, but always de- 

 terraiuately disposed along the sides of the main stalk or branch- 

 lets, and are never terminal ; ova contained in horny deciduous 

 vesicles scattered over the polypidom ; embryos PZa;mm-l ike. 



Genus YIII. HALECIUM, Ohn. 



Gen. Char. Polypidom rooted, plant-like : the stem composed 

 of aggregated subparallel capillary tubes; the branches alter- 

 nate, spreading bifariously ; cells tubular, subsessile, jointed at 

 the base, arising alternately from opposite sides, one under every 

 joint of the branchlet : ovarian vesicles irregularly scattered. 

 Polypes hydraform, scarcely retractile within their cells. 



