MIMOSELLID.^. 555 



exhibits the same structure, his name, of course, has pre- 

 cedence. 



Habitat. On stones and stems of Algse between tide- 

 marks, and on shell from moderately deep water. 



Localities. Sslcomhc Bay, on Flustrapajjyracea; Ilfra- 

 combe, on the Capstone, not uncommon ; dredged off the 

 Isle of Man (T. H.) 



Family IX. — Mimosellidae. 



ZoffiCiA contracted below, movable, deciduous, with an 

 aperture on the ventral side. 



Genus MIMOSELLA, Hincks. 



Der. Dim. of Mimosa, the Sensitive Plant. 

 MiJiosELLA, Hincks, Ann. N. H. 1851 : Landsborough : Hellei' : &c. 



Generic Character. — Zoarium plnjtoid, regularly 

 jointed, co7isisting of a creeping tubular base and erect 

 shoots, much and irregularly branched, branches opposite. 

 ZocECiA ovate, biserial, opposite, attached to the sides of the 

 stem by a basal joint, by means of ivhich they can be moved 

 to and fro and folded together. Polypides with a small 

 number of tentacles ; without a gizzard. 



MiMOSELLA is separated from the Valkeriida by its 

 movable cells, and more especially by the large aperture 

 oh the ventral aspect of the zooecium. The latter occupies 

 almost the whole of the front side, extending from the 

 top nearly to the base of the cell. It is closed by a thin 

 membranous covering, and, when the polypide is retracted, 

 is very inconspicuous and may most readily escape obscr- 



