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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.

Family Sertularidæ. — Thuiaria divergens, sp. nov. — (Plate xxiii., figs. 1, 2, 3.)

Family Sertularidæ.
Thuiaria divergens, sp. nov.
(Plate xxiii., figs. 1, 2, 3.)

Trophosome: Hydrocaulus simple, indistinctly and irregularly jointed, strongly fascicled below, becoming monosiphonic distally; height from 5 to 6 cm. Hydrothecæ alternate, one opposite the base of each pinna, and two on the same side, one of which is situated in the axil above and the other about 0·2 mm. below. The base of each of the cauline hydrothecæ possesses a thick chintinous process which extends across the internal cavity of the stem and becomes united with the opposite wall.

Pinnæ alternate, from 1 to 2 cm. in length and about 2 mm. apart; joints transverse, very irregular; one or two pairs of hydrothecæ to an internode, frequently two or more internodes without hydrothecæ on each pinna.

Hydrothecæ 0·7 mm, in height, 03 mm. in broadest diameter, diminishing to 0·2 at the apex; proximally they are opposite, distally they become subalternate, they are adnate for about one-third or one-half of their height, but not in contact with each other at the back; the free portion is abruptly bent outwards; the outline above is horizontal or slightly ascending, and evenly curved below; the terminal third exhibits numerous lines of growth. Aperture operculate, subquadrate, with four angles, one pair in a line with the axis, the other lateral.

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Gonosome: Gonangia ovate, borne on the front of a pinna at the base of a hydrotheca 1·7 mm. high, 0·5 mm. broad in the middle, and 0·3 mm. at the neck, which is about as high as broad, surface with from 8 to 10 distinct annulations. Aperture square with four membraneous opercular teeth.