86 DUBLIN UNIVERSITY 



row from the inner aspect of each joint of each branch, so that the tri- 

 angular space within the fork is closely strung, like a harp, with pa- 

 rallel strings of cells (Plate VIII., Fig. 3). The anterior aspect of the 

 cell is narrow and slipper-shaped. 



The mouth is placed near the top of the cell, large and crescentic, with 

 a thin projecting upper rim. A movable semicircular operculum, with 

 a raised edge, covers, or hangs below, the cell mouth. The operculum 

 has at its base on either side a projecting triangular catch, which fits 

 into a notch in the lip. One would almost expect this apparatus to 

 shut with a snap like the clasp of a purse, it is so nicely fitted, and so 

 eminently mechanical-looking. 



Below the cell aperture a long, depressed area stretches nearly to the 

 base of the cell. The cell is much compressed laterally ; the side view 

 is much broader, and almost reniform. The cell- wall is double through- 

 out, with a wide space between the layers, thus forming two distinct 

 chambers, the inner not even resembling the outer in form. The ante- 

 rior depressed area is formed by the outer layer alone, so that beneath 

 there is still another space before reaching the inner wall. In the cen- 

 tre of the area a tube passes through this space, uniting two correspond- 

 ing apertures, one in either membrane, and thus communicating di- 

 rectly with the interior of the cell. The side view shows the inner 

 chamber as a doubly bent expansion of the common tube of the ccence- 

 cium. 



Here and there one of the cells of a row is about double the size of 

 the rest. These large cells have their opercula always closely shut. They 

 are slightly more gibbous than the others, but scarcely differ from them 

 in form. They are, doubtless, the ovicells. 



The ccencecium is small and delicate, very calcareous, with a beau- 

 tiful pearly lustre. Parasitical on Fucoids. 



Fremantle District, "Western Australia (Dr. Harvey). 



Subsect. 2. Bl-MlJLTISERT A LA RIA. 



Family 2. — Salicornariadae (Busk). 

 1. — Salicornaria (Cuv.). 

 1. — S. tenuirostris (Busk). 

 Bass's Strait ; Dr. Harvey. 



