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Claus, 1877

Composite description based on Haeckel, 1880 (as Undosa undulata, from Fernando Po, Guinea, West Africa, best description), and partly on Mayer (1910), Thiel (1966), and Pagès et al. (1992). Poorly known, only Haeckel providing a reliable account of undamaged adult material. Umbrella quite flat, jelly moderately thick, clear; 120 mm by 40 mm recorded from life (Haeckel, 1880). Rhopalia 8. In a 32-tentacled specimen, rhopalial lappets 16, each cleft in two, each half-lappet semi-circular to pointed; tentacular lappets each as broad as a full rhopalial lappet but not cleft, semi-circular (and so its semi-circle twice the width of that of the half-rhopalial lappet) to pointed; in a specimen having three tentacles between one rhopalium and next, a primary tentacle in the centre of the paramere was flanked by one secondary on each side. Thus between one rhopalium and next are, in sequence, a double rhopalial lappet, secondary tentacle, tentacular lappet, primary tentacle, tentacular lappet, secondary tentacle, and a double rhopalial lappet, then next rhopalium. Tentacles 48. Haeckel recorded (in a 120 mm diameter individual, evidently from life) the 16 primary tentacles 2-3 times bell radius, 16 secondaries half "the size of" ("so gross als") the 16 tertiaries, unclear if 3 times narrower or shorter (A. Svoboda, pers. comm.). In specimens having 48 tentacles, possibly the 16 tertiary tentacles develop from tissue at base of clefts in rhopalial "double" lappets. Subumbrellar musculature (?) not described. Mouth arms thick, broad, "resemble those of Aurelia aurita, but margins more curtain-like, more folded, with numerous tentacular filaments; gutters of the mouth-arms very deep" (Mayer, 1910, after Haeckel). Stomach circular, wide, occupying central 1/2 of disc.
Adradial canals 8, unbranched nearly to margin, the 8 perradial and interradial canals producing basally branches which run at ca. 45° towards distal point of adradial canals (at periphery), much anastomosing peripherally but leaving 16 near-triangular patches of mesoglea internally without gastrovascular canals (see diagram, Discomedusa lobata). Marginal ring-canal following edge of disc in 16 shallow to nearly flat curves, in sub-crenate pattern. Gonads 4, in much-folded ribbon lying near stomach periphery, sac-like when mature, projecting from floor of subumbrella. No subgenital ostia.
Coloration: 16 radial exumbrellar streaks reported (Haeckel, 1880), comprising numerous dark brown pigment spots and nematocyst warts arranged in star-pattern aligned with ridges in underlying mesoglea.

Discomedusa lobata