LEPTOMEDUS/E — OBELIA, TIAROPSIS. 257 



Obelia serratula Bale. 



Obelia serratula, Bale, 1888, Proc. Linnean Soc. New South Wales, vol. 3, p. 757. — Thornely, 1900, Zoological Results, A. Willey, 

 part 4, p. 453, plate 44, fig. 5, Cambridge, England. 



Stems branched and with stolons growing downward from peduncles of hydrothecae. 

 Stems over 10 mm. high. Hydrothecae short, broad, flaring, with about 10 to 12 large 

 triangular teeth. Floor of hydrotheca raised above base, leaving a large cavity beneath it. 

 The gonotheca is borne upon a short ringed stem, is oval, truncated above, and with smooth 

 outer surface. The gonothecae arise from the sides of the stems and each bears several 

 medusae. East coast of Australia, New Britain, South Pacific. Found in shallow water — 40 

 fathoms — on ropes, etc. 



Obelia linearis Thornely. 

 Obelia linearis, Thornely, 1900, Zoological Results, A. Willey, part 4, p. 453, plate 44, fig. 6, Cambridge, England. 



Stems branched, 7 mm. high. Hydrothecae deep, with about 12 blunted teeth on margin, 

 pedicels tapering, ringed throughout with 12 to 16 rings. Gonothecae borne in axils of peduncles. 

 They are elongate, oval, smooth, and with orifice prominent, recurved, and gaping. There 

 are a number of medusa-buds within the gonotheca. Stems horn-colored below, transparent 

 above. Tropical Pacific. (New Britain ?) 



Obelia delicatula Thornely. 



Obelia delicatula, Thornely, 1900, Zoological Results, A. Willey, part 4, p. 453, plate 44, fig. 7, Cambridge, England. 



Stems 4 mm. high, simple and unbranched, borne on a creeping stolon, which also bears 

 gonothecae; ringed at their bases, and here and there above, and bear 3 or more rings under 

 the hydrothecae. Hydrothecae elongate, goblet-shaped, with about 12 blunt teeth at rim. 

 Gonothecae blunt, short, with flaring margins, and with several medusa-buds arising singly 

 from basal stolon of hydrothecae. Blanche Bay, New Britain, South Pacific. 



Obelia angulosa Bale. 



Obelia angulosa, Bale, 1888, Proc. Linnean Soc. New South Wales, ser. 2, vol. 3, p. 752, plate 12, fig. 3. 



Stems monosiphonic, 25 to 50 mm. high, with numerous suberect branches given off 

 from main stem. Stem and branches more or less zigzag, with 3 to 5 rings above origin of 

 each pedicel. Pedicels short, ringed, with 3 to 5 annulations, or with central part smooth, and 

 with entire pedicel twice as long as hydrotheca. Hydrothecae alternate, funnel-shaped, gen- 

 erally slightly constricted at level of "floor" which is some distance above base and somewhat 

 oblique. Margin everted, not toothed, but uneven. Gonothecae long, slender, urn-shaped, 

 with an everted neck. Pedicel with 3 to 5 rings, upper part of capsule with faint, not prominent 

 rings. Gonothecae 2.5 times as long as the hydrothecae. Several medusae in each. Pana- 

 matta River, Australia. 



Obelia andersoni Hincks. 



Obelia andersoni, Hincks, 1887, Journ. Linnean Soc. London, vol. 21, p. 132, plate 12, figs. 2-4. — Thornely, 190c, Roy. Soc* 

 London, Report on Pearl Oyster Fisheries of Gulf of Manaar, Ceylon, part 2, p. 11 J. 



Stems nearly straight with alternate pedicels; annulated at points of origin of pedicels 

 and above them. Pedicels ringed throughout with 7 to 8 rings. Upper three-fourths of 

 calycle cylindrical and lower one-fourth conical. Calycle expands slightly near orifice. Rim 

 has io to 16 narrow, high, bluntly pointed teeth. 



The gonothecae arise from main stem near base of pedicels and are borne on short- 

 ringed stalks; narrow at base, expanding upwards, truncate at top. Medusae are produced. 

 Found on Nrlltn oculata, in the Mergui Archipelago off the coast of Tenasserim. The pecu- 

 liar conical lower part of the calycle is characteristic. 



Genus TIAROPSIS L. Agassiz, 1849. 



Thaumantias, Sars, 1835, Beskriv og Jagtt*ag., p. 26, taf. 5, fig. 12. 



Thaumantias (in part), Forbes, 1848, British Naked-eyed Medusa 1 , p. 45. 



Tiaropsis, Agassiz, L., 1849, Mem. Amer. Acad., vol. 4, p. 289; 1862, Cont. Nat. Hist. U. S., vol. 4, pp. 308,355. — Agassiz, A., 



1865, North Amer. Acal., p. 69. — Haeckel, 1879, Syst. der Medusen, p. 178. — Linko, 1900, Travcaux de la Soc. Imp. 



des Nat., St. Petersbourg, tome 29, p. 155. — Maas, 1905, Craspedoten Medusen der Siboga Expedition, p. 29.— Browne, 



1005, Proc. Royal Soc. Edinburgh, vol. 25, p. 773. 

 Tiaropsedium, Torrey, 1909, University California Publications, Zool., vol. 6, p. 19. 



