with descriptions of some netv species. 359 



rotating by the action of cilia before escaping into the intestine. 

 The intestinal tube shortly after leaving the stomach expands 

 into a kind of sac. 



New Species of Vesicularian Zoophyte. 



The production which I am about to describe I believe to be 

 quite new to the British fauna. Whether it be known or not to 

 foreign authors I am unable to say. 



It belongs to the family Vesiculariadse of Dr. Johnston^s work, 

 and is much the most beautiful of its tribe. The peculiar struc- 

 ture of the cells renders necessary the formation of a new genus 

 for its reception. In general character it is allied to Vesicularia. 



Family Vesiculariad^. 

 Genus Mimosella (Hincks). 



Polypidom rooted, confervoid, homy, jointed and variously branched; 

 cells ovate, biserial, opposite, with a basal Joint, by means of 

 which they can be moved to and fro, and folded together on 

 the branches ; polypes with eight tentacula. 



Species Mimosella gracilis (Hincks). 



From a creeping fibre which spreads over the surface of Fuci, 

 rise graceful, tapering stems, pinnate, much attenuated towards 

 their extremities, and running out into filamentary, tendi'il-like 

 prolongations. These stems are commonly from an inch to an 

 inch and a half in height. They are jointed at intervals ; and 

 immediately below each joint spring two opposite pinnae, also 

 jointed, tapering and slightly curved. 



The pairs of pinnse do not all lie in the same plane. Along 

 these are set the cells, which are ovate, elongate, biserial and 

 opposite. Each cell is attached to a small prominence on the 

 side of the pinna, which is perforated. A circular orifice on one 

 side of the cell near the base fits over this, and o, joint is thus 

 secured, by means of which the polype can move its dwelhng 

 forward in one dii-ection and back again. This is frequently 

 done. The polj'pes are continually swaying their cells to and 

 fro. Sometimes all the cells on the pinna are folded together on 

 the upper side, just as the leaflets close on the leaf of the sensi- 

 tive-plant {Mimosa), and hence the generic name. When spe- 

 cimens are dried or preserved in fluid, the cells are generally in 

 this condition, and on slight inspection might be pronounced 

 unilateral. Towards the base of each pinna the cells are long 

 and oval ; as they approach the apex they become short and glo- 

 bose, and at last arc nothing more than little round excrescences. 



The polypes have eight arms, and are furnished with a gizzard. 



