Cells in sets of six--three on each side; a single axillary cell in each dichotomous division of the polypidom. Ovicell pedunculate ovoid, adnate to the rachis, with a lateral opening.
Habitat: Off Cumberland Isles, 27 fathoms.
As this differs in the number of cells in each set, as well as in the form of the cells, and in the form and position of the ovicell, it appears irreconcilable with Lamouroux' P. quadridentata. According to the figure given of the latter the ovicell is not adnate, and is spirally grooved.
3. PLUMULARIA, Lamarck.
a. Angiocarpeae--ovicells enclosed in siliquose, costate receptacles.
1. P. huxleyi, n. sp.
Plumularia--Huxley, Philosophical Transactions Part 2 1849 page 427 plate 39 figures 43 and 45.
Cells cup-shaped, shallow; mouth nearly vertical, subquadrangular, margin subcrenate, plicate; with a small acute central denticle in front, and a wide shallow notch behind. Rostrum twice as long as the cell, arising from the rachis by a broad ventricose base, adnate the whole length of the cell, narrow upwards and slightly expanded again at the summit; lateral processes very short and wide, canalicular adnate. Costae of ovarian receptacle numerous, each with a single branch near the bottom, and beset with small cup-like processes, and not connected by a membrane.
Habitat: Port Curtis. Off Cumberland Islands, in 27 fathoms fine grey mud.
Colour yellowish white. Polypidom about 6 inches high, rising with a single flexuose stem, which is naked at bottom, and afterwards gives off alternate branches, bifariously disposed at each angular flexure. Branches simple, 2 to 3 inches long; pinnules about 1/4 inch. The construction of the ovarian receptacle in the present section of the genus Plumularia is well exemplified in this species, owing to the comparative simplicity of the elements of which it is composed.