172 Mr. A. H. HassalPs Catalogue of Irish Zoophytes. 



about an inch and a half in height ; each tuft is composed of nume- 

 rous separate polypidoms, closely interwoven with each other, and 

 dichotomously branched. The cells are of an oblong square form, 

 slightly enlarged distally, and furnished with a globular operculum 

 somewhat similar to that of F. avicularis. 



F. avicularis. This species has four spines at the top of each cell. 



Parasitic on other corallines ; rare ; Dublin bay. 



F. membranacea. On the frond of Laminaria digitata; very 

 abundant ; common. 



F. Hibernica. Polypidom encrusting calcareous, white ; cells 

 hexagonal, excavated, dotted on the inside. — A. H. 



The only specimens I have obtained of this are parasitic on an 

 Ascidia ; I have little doubt, however, of its being a new species. 

 The Flustra to which it bears the closest resemblance is perhaps 

 F. carbasea, but I have never met with it on this part of the Irish 

 coast. See Plate VII. fig. 1. 



Cellularia. 



Cellularia ciliata. — Dublin bay ; rare. 



C. scruposa. On the roots of most corallines and old shells; 

 abundant ; Dublin and Killiney bays. 



C. reptans. Everywhere very common. 



C. Avicularia. This species is, I think, misplaced ; it ought ra- 

 ther to be associated with Flustra than Cellularia. 



Dublin bay; rare. 



Acamarchis. 

 Acamarchis plumosa. — Dublin bay ; rare. 



Farcimia. 



Farcimia salicornia. " Articulations cylindrical; cells rhomboidal, 

 plain." 



Farcimia sinuosa. Cells rounded above, excavated below for the 

 reception of the head of the succeeding cell ; aperture semicircular, 

 situated in the upper third of each cell. — A. H. 



I have but little hesitation in pronouncing this to be a new spe- 

 cies*. It differs from the ordinary species in the greater size of the 

 cylinders, in the shape of the cells (too material to be the result of 

 any accidental circumstances), and above all, in the position of the 

 aperture, which in this is placed in the upper part of each cell, while 

 in F. salicornia it is exactly central. This last I consider to be the 

 most important distinction of all. The number of the cells on each 

 cylinder is also much greater than in the preceding species. See 

 Plate VI. fig. 1. 2. 



* Among several specimens of salicornia, collected by Mrs. Alder and 

 Miss Amelia Hunter, at Blackrock, Dublin bay, I observed some of Farci- 

 mia sinuosa, agreeing in every particular with my own previously obtained 

 at Menion, about two miles from the former place. The authority for this 

 new species does not now, therefore, rest upon the examination of a single 

 specimen. 



