38 THE VOYAGE OF H.M.S. CHALLENGER. 



operculum, and in this character resembles Cellaria. The vibraculum has an articular 

 caput, and has various projections for the attachment of muscles, but the shape will best 

 be understood from the figure. 



The dorsal surface shows the pores stellate, or, perhaps more correctly, there are 

 tubercles round the pores, giving a stellate appearance. 



Habitat. — Port Jackson, 30 to 35 fathoms; Holborn Island and Barnard Island, 

 Australia. Fossil — Victoria and South Australia. 



Farciminaria biseriata, n. sp. (PI. I. figs. 2, 3). 



This I found from Station 122 growing on Bifaxaria corr'rigata, and afterwards 

 another small specimen growing on Kinetoskias. The zoarium is erect, attached by 

 horny tubes, and in the larger specimen the zocecia are distinctly in pairs and opposite, 

 wliereas in the smaller one they must be called alternate, with the zooecia facing in two 

 directions ; the sides of the zooecia are much raised above the flat central part, which is 

 in the same plane as the operculum. The surface is distinctly granulated, with the 

 granulations very marked at the edges. The oral aperture is rounded above and straight 

 below, with a calcareous bar at the base, formed by a thickening of the wall, and on this 

 bar there are two minute knobs or denticles. 



The horny tubes usually arise from the front of the zooecium, but the position is not 

 constant. 



It is difficult to see where this should be placed, and the description of FarciminaHa 

 would require enlarging to receive it, as there is more calcareous matter in it than is 

 usual, and the arrangement of the zooecia is diff"erent ; but these are not characters of 

 sufficient importance to justify a new genus, and I therefore place it provisionally with 

 Farciminaria. 



Habitat.— Sta.tion 122, lat. 9° 5' S., long. 34' 50' W.; 350 fathoms. Red mud. 



Flustra separata, n. sp. (PL I. fig. 9). 



The zoarium appears to be broadly lobate, and the two layers are only attached at 

 the border of the zoarium, so that if the outside zooecia are cut through the whole 

 separates like two sheets of paper. 



The zooecia are oval without any spines, and they are sometimes replaced by large 

 vicarious avicularia, closed by large spatulate mandibles, having two strong chitinous 

 ridges starting from near the distal end, and curving out to the proximal corners. 



There are on the distal wall 5 to 6 small rosette plates. 



In some cells a small digitiform process hangs down inside from near the aperture, 

 and expands at the end in three or four globular projections. This is seen to be the 



