Scandia

? Scandia sp.

(fig. 5D, table 9)

Material examined. Stn. 3: 26.01.2008 —two hydrothecae, no gonothecae, on alga.

Description. Colony epiphytic, stolonal, composed of two hydrothecae of different sizes. Hydrothecal pedicel, of variable length, corrugated. Hydrotheca cylindrical, asymmetrical and bent slightly to one side; walls smooth to imperceptibly undulated; margin everted, oblique; basally, an annular thickening of perisarc. One hydrotheca has renovated margin. Gonotheca absent. Nematocysts not seen.

Remarks. Due to its occurrence on algae and not on hydroids, this species is provisionally included in the genus Scandia Fraser, 1912. No positive identification is possible in the absence of gonothecae.

Distribution. The present material originates from Guadeloupe.

TABLE 9. Measurements of? Scandia sp., in µm. (1)Primary hydrotheca.

Material examined. Stn. 6: 23.03.2008 —several dense, sterile colonies, on Halimeda sp. (MHNG INVE 61001).

Description. Colony stolonal, with extremely minute, individual hydrothecae arising irregularly from slender (20–30 µm wide), smooth, creeping hydrorhiza. Hydrothecae borne on short, transversely annulated pedicels (2–3 slightly marked “annuli”). Hydrotheca tubular, radially symmetrical, 165–205 µm long; walls nearly parallel, though imperceptibly widening in middle region (maximum width 50–55 µm); basally tapering into pedicel; either diaphragm or annular thickening absent; distally slightly flaring, 45–60 µm wide at aperture; margin circular, rim even; occasionally renovated once. Perisarc of hydrotheca smooth, moderately thin. Hydranth with 10–12 filiform tentacles. Gonosome unknown. Nematocysts: a few large, bean-shaped heteronemes (15.7–20.0) × (6.4–7.8) µm, most probably arranged in a belt below the tentacles; small capsules (4.8–5.1) × (1.3–1.4) µm, in tentacles.

Remarks. This species is provisionally included in the genus Lafoea Lamouroux, 1821 based on the following observations: the colony has no nematothecae; the hydrotheca is long, tubular, borne on a very short pedicel; basally there is no diaphragm or annular thickening; the hydrothecal aperture is devoid of an operculum.

Although some members of Lafoea, e.g. L. dumosa (Fleming, 1828), could exhibit both stolonal and erect growth forms (sometimes simultaneously within the same colony), the present species forms exclusively stolonal colonies. Moreover, its size is much smaller than that of its presumed congeners (table 10).

Data on the nematocyst complement of the various species of Lafoea are scarce. Large, bean-shaped isorhizas have been reported in both L. annulata (Watson, 2003) and L. dumosa (Schuchert 2001a; Galea, personal observations made on Chilean material). However, the present species is provided with heteronemes instead of haplonemes.

Distribution. Known only from Les Saintes.