Narrative of the Voyage of H.M.S. Rattlesnake Volume I Part 40

Sertul. gayi. (Lamouroux. Exp. page 12 plate 66 figure 89 has four teeth.)

This species occurs also on the south coast of Patagonia, and the Straits of Magellan; in the latter locality, however, the habit is much more robust.

3. S. crisioides, Lamouroux. (Dynamena.)

Cells adnate, conical, slightly curved, truncate at bottom, narrow at top; mouth vertical, external.

Habitat: Off c.u.mberland Islands, 27 fathoms.

Very like a Thuiaria, but the cells are not immersed, though very closely adnate, and the outer angle of the square base of each cell is in contact with the upper and back part of the one below it, so that a small triangular s.p.a.ce or opening is left below each cell. The branches are very regularly alternate; and the polypidom is of a light brownish colour.

(b) Cells secund.

4. S. pristis, (B.).

Idia pristis, Lamouroux.

Cells tubular, all contiguous or adnate to each other, and to the rachis, upper half curved laterally, lower half closely adnate, almost immersed in the rachis; mouth looking upwards, rounded, expanded, almost infundibuliform, border slightly scalloped towards the rachis, and projecting externally. Ovicell cyathiform, long narrow with circular rugae. Mouth as large as the diameter of the cup, margin very slightly everted.

Habitat: Prince of Wales Channel, Torres Strait, 9 fathoms. Off c.u.mberland Islands, in 27 fathoms, fine grey mud.

I see no reason why the present species should not come under Sertularia.

It is peculiar from the position and extreme contiguity of the alternate cells. The ovicells arise from the back of the rachis towards the side.

When viewed posteriorly, the cells are seen through the transparent rachis, and it might thus at first sight appear as if the rachis itself were cellular and not tubular, but such is not the case. The tube is wide and continuous from end to end.

2. Cells opposite (sometimes alternate on the stem). (Dynamena).

(a) Cells distichous.

5. S. subcarinata, n. sp.

Cells tubular, upper half divergent, ascending. Mouth looking upwards, circular, with an anterior and two lateral broad, expanding teeth. A narrow angular line or keel down the front of the cell. Ovicell ---- ?

Habitat: Ba.s.s Strait, 45 fathoms dead sh.e.l.ls.

Colour white, transparent, growth small, straggling. Branches irregular, divaricate nearly at rightangles, subalternate. The three expanding teeth and the anterior ridge or keel, besides its habit, distinguish it from a Tasmanian species with which alone can it be confounded. The cells are large.

6. S. patula, n. sp.

Cells tubular, upper third free, divergent ascending. Mouth perfectly round, looking upwards and outwards, margin entire everted. Ovicell ---- ?

Habitat: Ba.s.s Strait, 45 fathoms, dead sh.e.l.ls.

Colour whitish. A small parasitic species, with opposite branches.

7. S. Orthogonia, n. sp.

Cells tubular, nearly half free, divergent laterally at a right angle.

Mouth looking directly outwards, border entire, slightly everted. Ovicell ---- ?

Habitat: Prince of Wales Channel, Torres Strait, parasitic upon S.

pristis.

Very like the preceding in habit and size, of which it may possibly prove to be a variety. The cells, however, throughout the whole of the polypidom are of precisely the same character, in each form, and exhibit no intermediate steps. In the present species the cells are much longer, rather narrower, and the upper half is turned out abruptly at a rightangle, whilst in the former they ascend at an angle of 45 degrees, and the free portion is much shorter. The branches in both are opposite; the ovicells are unfortunately absent in each.

8. S. mutulata, n. sp.

Cells compressed or flattened, from side to side; sometimes angular, lower half adnate, upper half divergent, projecting like a bracket. Mouth looking directly upwards, narrow oblong, quadrangular. Ovicells aculeate, with strong widely set spines, pyriform depressed.

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

Colour light olive grey. Polypidom about three inches high, irregularly ?

branched, branches not opposite. The cells are distichous, and of a very peculiar form, but varying in some degree according to their situation.

The younger (?) cells on the secondary branches are flat on the inferior or outer aspect, with two angles on each side, or are quadrangular; whilst the cells on the stems or older or fertile branches are usually rounded below, or on the outer side, and thus have only one angle on each side. The mouth varies in shape according to the cell; in the former case being a regular long rectangle, whilst in the latter it is rounded on the outer side. The ovicells are placed in a single series on one side of the rachis, as in S. digitalis, but are widely different in form.

9. S. operculata, Linn.

Habitat: Swan Island, Banks Strait.

This species occurs in all parts of the world. It is to be carefully distinguished from S. bispinosa, Gray--also an Australian and New Zealand species, but which does not occur in the present collection.

b. Cells (on the branches) secund, contiguous.

10. S. divergens, Lamouroux.

Cells urceolate, much contracted towards the mouth; upper half free, divergent, projecting laterally almost horizontally; mouth small elliptical, with the long axis looking directly outwards; two lateral teeth. Ovicell smooth, rounded, ovoid; oral margin not elevated.

Habitat: Swan Island, Banks Strait.

Colour light yellowish: parasitic upon a fucus. Height from 1/4 to 1/2 inch; simply pinnate, branches distant, regularly alternate. The stem is divided into internodes, from each of which arises a single branch. The cells on the stem are alternate.

b. Cells secund.

11. S. trigonostoma, n. sp.

Cells ovoid, gibbous, much contracted towards the mouth. Very small portion free, projecting forwards and outwards. Mouth looking outwards and forwards, triangular, with a short blunt tooth on the external angle.

Ovicell ---- ?

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

Colour very light yellowish. Polypidom simply pinnate, about two inches high: longest pinnae about half an inch. Cells small adnate, projecting suddenly at top, and much contracted at the mouth. The mouth is of a triangular form, the longest side of the triangle being below. The cells are placed in pairs, but one is always a little higher than the other (subalternate) and one pair is placed on each internode on the pinnae.

The stem is also indistinctly divided into internodes, from each of which a single pinna is given off alternately on opposite sides, and besides the pinnae there are three cells on each internode, two on the side from which the pinna springs, and on the opposite side alternate in position to the other two.

12. S. digitalis, n. sp.

Cells digitiform, slightly curved to the front, mouth circular, looking directly upwards. Margin entire, expanded. Ovicells long-ovoid, muricate, spines numerous crowded, mouth prolonged, tubular.

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