Habitat:  Prince of Wales Channel, Torres Strait, 9 fathoms.

Colour pale buff.  Polypidom five or six inches high, consisting of a strong straight, tapering stem, sometimes with a single ascending branch given off near the bottom; stem and branches pinnate; pinnae 1 1/4 to 1 1/2 inches long; alternate, and arranged with the utmost regularity, of uniform length, till near the summit, when they shorten rapidly, so as to give the polypidom a rounded truncate end.  The pinnules are excessively fine and delicate, not more than 1/10 to 1/12 inch long, and very closely set, so that the whole polypidom has the most exact resemblance to a beautiful silky quill feather.

10.  P. macgillivrayi, n. sp.

Cells campanulate, deep, rounded at bottom; margin subplicate, entire.  Rostrum large, rising from the cell, adnate the whole length of, and as long as, the cell; the upper third constitutes a cup distinct from the lower portion; lateral processes adnate, wide, short, curved upwards, canalicular or tubular.  Costae of ovarian receptacle connected by a membranous expansion.

Habitat:  Louisiade Archipelago, reefs at low water.

Colour bright brownish buff.  Polypidom six to seven inches high, consisting of a strong central stem, giving off opposite branches, at regular intervals, and bifariously disposed.  Pinnules about 1/8 inch long, closely set.

b.  Gymnocarpeae—­ovicells naked.

11.  P. effusa, n. sp.

Cells urceolate; deeply emarginate posteriorly, entire in front, ventricose below; a small pedunculate infundibuliform process attached in front to the projecting portion of the rachis on a level with upper border of the cell.  Ovicell ——­ ?

Habitat:  Prince of Wales Channel, Torres Strait.

Colour buff.  Habit very peculiar.  The polypidom rises to a height of seven or eight inches, with a long slender waving, but upright stem, which is naked inferiorly, and above gives off numerous straight or waving branches, again subdividing into other shorter straight ramules, about an inch long.  The branches and branchlets are both pinnulated; the pinnules are not more than 1/10 to 1/12 inches long, extremely delicate and minute, so as in the dry state to be scarcely visible.  The transition from the former section of the genus Plumularia to the present, is well shown, through P. macgillivrayi and the present species.

12.  P. campanula, n. sp.

Cells campanulate, border entire; lateral and anterior appendages canalicular.  Branches alternate.  Ovicells ——­ ?

Habitat:  Bass Strait, 45 fathoms dead shells.