EKITISH ZOOPHYTES. 323 



Genus Mimosella, Hindis. {Mimosa, the Sensitive 

 Plant.) 



Zoarium phytoidj regularly jointed, consisting of a 

 creeping tubular base and erect shoots^ much and ir- 

 regularly branched, branches opposite. Zooscia ovate, 

 biserial, opposite, attached to the sides of the 

 stem by a basal joint, by means of which they can 

 be moved to and fro and folded together. Polypides 

 with a small number of tentacles ; without a gizzard. 

 — T. H. 



1. M. GRACILIS, Binds. 



Yalkeria cuscuta {R. Q. C). Plate XXIII. fig. 6. 



Hab. : Torbay [T.H.), Cornwall [E. Q. C), Guernsey 

 {Coojjer). 



This beautiful species is found on Halidrys siliquosa, 

 upon which it rises to a height of one to four inches. 

 The zoarium is exceedingly graceful, and grows in a 

 plant-like manner. The stem is regularly jointed, and 

 gives off irregular branches which are opposite, and 

 bear the zooecia. The latter are " ovate, elongate, 

 biserial and opposite, and attached to small prominences 

 on the side of the branch, which is perforated. A cir- 

 cular orifice on one side of the cell near the base fits 

 over this, and a joint is thus secured, by means of 

 which the polyp can move its dwelling forward in one 

 direction, and backward.''^ The cells on a branch are 

 often folded together on the upper side " just as the leaf- 

 lets close on the leaf of the sensitive plant {Mimosa)." 

 The cells are rounded at the end of each branch, and 

 become more and more elongated as they near the 

 stem. 



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