The Atoll of Funafuti, Ellice group : its zoology, botany, ethnology and general structure based on collections made by Charles Hedley of the Australian Museum, Sydney, N.S.W.
Subclass Zoantharia. — Order Antipatharia. — Family Antipathidæ. — Antipathella brookii, sp. nov
Antipathella brookii, sp. nov.
The corallum is erect, pinnate and branched in a single plain; it is 8 cm. in height and 6·5 cm. broad; the stem (?) at the base is 1 mm. in diameter.
The specimen consists of two main fronds, having the shorter branches fused here and there at the base but free at the summits. Each frond gives off a series of alternate—rarely opposite—pin-nules. The primaries arise almost at right angles, and are slightly curved upwards at a short distance from their origin. The secondaries also are at right angles to their support; they are generally straight, simple, or with numerous short branchlets, occasionally a few are elongate and slightly curved.
The primary pinnules are from 2 to 3 cm. in length, and pretty regularly 4·3 mm. apart; the secondaries are from 5 to 15 mm. in length and 3 mm. apart; the tertiary pinnules vary from 1 to 7 mm. in length.
The polyps on the pinnules are situated on the anterior surface, forming a single longitudinal series; there are six to 1 cm.; they are about 1·1 mm. in length, and are separated from each other by short intervals varying from 0·2 to 0·4 mm.
The polyps do not commence at the bases of the branchlets; there is generally a nude space—from 0·4 to 0·6 mm. in length—at their point of origin from the stem. The latter also usually has a similar polyp-less space above and below the base of a branchlet. On the stouter portions of the corallum a few of the polyps are radiate or subradiate, elsewhere they are elongate. There are two distal and two proximal tentacles situated in a line with the pinnule, and two placed transversely—one on each side of the mouth—which are generally smaller and inserted on the sides of the pinnule, not on the anterior surface as is the case with the other two pairs. The tentacles are about 0·25 mm. in length. The oral prominence is slightly elongate transversely, it is 0·1 mm. in height, O·5 mm. in its longer and 0·35 mm. in its shorter dia-meter. The mouth is a narrow, elongate, slit-like opening, with page 385an irregular crenated margin. The zooids are not sufficiently well preserved to afford accurate internal structural details.
The spines near the apices of the pinnules are short and some-what triangular; below they are elongate and subcylindrical, with smooth, acute, abruptly tapering summits. They are arranged in longitudinal rows and frequently exhibit a spiral arrangement running from right to left; five rows may be seen from one aspect, four of which are included in the spiral arrangement. Many of the spines on the stouter pinnules are given off at right angles, generally they are slightly inclined upwards, their length is about 0·3 mm., and measured from apex to apex in a spiral 0·4 mm. apart.
This species is allied to A. tristis and A. atlantica.