I 



84 AMKEICAN HYDROIDS. 



OBELU SURCOLARIS Calkins. 



•Plate 22, figs. 1-2. 



Obelia surcularis Calkins, Some Hydroids from Puget Sound, 1399, p. 355. 



Obelia surcularis Hartlaub, Hydroiden aus dem Stillen Ocean, 1901, p. 353. 



Obelia surcularis Mayer, Medusae of the World, vol. 2, The Hydromedusse, 1910, p. 353. 



Obelia surcularis Fbaser, West Coast Hydroids, 1911, p. 40. 



Trophosome.^ — Colony 17 mm. in height, consisting of a single regularly branched stem. 

 Main stem slender, flexuose, regularly branched with two or three rather feebly defined annu- 

 lations above each branch origin. Branches regularly alternate and often ending iii greatly 

 elongated tendril-hke filaments which are clavate at the ends.^ The branches resemble the 

 mam stem m stnicture and bear alternate pedicels. The pedicels are short usually less than 

 haM the length of the hydrothecse, are very thin and hyalhie and show irregular fault corruga- 

 tions or annulations. They taper regularly in size from proximal to distal end. Hydrothecse 

 in the foim of inverted cones with slightly bulging sides. The margin is entire and the dia- 

 phragm is very low and there is no distmct basal chamber. Hydranths of the usual campanu- 

 larian type with about 24 tentacles. 



Gonosome. — Gonangia borne on the branches in the axils of pedicels or branches. They 

 are slender, with their diameters increasing to the distal end where it is about one-third of the 

 total height. There is often a well-defined rim aroimd the shoulder of the gonangimn, above 

 which is a short sloping collar surroundmg the terminal aperture. The gonangia are filled with 

 numerous medusa buds which surround the blastostyle. Calkins says the mature medusae 

 have 24 tentacles. 



Distribution. — The type and only known locality is Scow Bay, Port Townsend Harbor, 

 Washington. 



Bathymetric distribution, 1 to 10 fathoms (?). 



OBELIA FLABELLATA (Hincks). 



Plate 22, figs. 3-4. 



Campanularia Jiabellalii Hincks, On new British Hydroida, Ann. Mag. Nat. Hist., ser. 3, 1866, vol. 18, p. 297. 



Obelia flabellata Hincks, British Hydroid Zoophj^es, 1868, p. 157. 



Obelia flabellata Verrill, Invertebrate Animals of Vineyard Sound, 1873, p. 728. 



Obelia flabellata Winther, Fortegnelse over de i Danmark Hydroider, 1874-80, p. 237. 



Obelia flabellata Merejkowsky, New Hydroida from Ochotsk, etc., Ann. Mag. Nat. Hist., ser. 5, vol. 1, 1878, p. 323. 



Laomedea (Obelia) flabellata Levinsen, Meduser, Ctenophorer og Hydroider fra Gronlands Vestkyst, 1893, p. 27. 



Obelia flabellata Hartlaub, Die Hydromedusse Helgolands, 1897, p. 451. 



Obelia flabellata Hargitt, Synopsis N. A. Invert., Hydromedusse, No. 2, Amer. Nat., vol. 35, 1901, p. 382. 



Obelia flabellata Nutting, Hydroids of the Woods Hole Eegion, 1901, p. 350. 



Obelia flabellata Jaderholm, Northern and Arctic Invertebrates, pt. 4, Hydroiden, 1909, p. 62. 



Laomedea longissima (part) Broch, Die Hydroiden der arktischen Meere, 1909, p. 229. 



Obelia plana Mayer, Medusae of the World, vol. 2, The HydromedusEe, 1910, p. 249. 



Obelia flabellata Stechow, Hydroiden der Miinchener Zoologischen Staatssammlung, 1912, p. 356. 



Tropho'some.^ — Colony 4.2 cm. in height, main stem flexuose, monosiphonic, dark brown 

 in color, hghtenuig distally and with a series of 3 or 4 annulations above each branch or pedicel 

 origin. Branches alternate, themselves branching dichotomously until each branch with its 

 ramifications presents a flabeUate form. Pedicels alternate, very short, usually much shorter 

 than the hydrothecas and annulated throughout. Hydrothecse campanulate, short, subtri- 

 angular in outline and with an entirely even rim. The hydrothecal walls are thick and the 

 outlines firm and pronounced. 



' Description of a specimen from Dr. Gary N. Calkins, the original describer, labeled "Puget Sound." 

 - This structure greatly resembles that described by the author in his discussion of " Stoloniferous reproduction." 

 American Hydroids, part 1, The Plumularidse, 1900, p. 43. It is not unlikely that the condition found in Obelia surcu- 

 laris is a temporary one, and not a specific character. 



' Description of specimen collected by the "Albatross" from station 2765, lat. 36° 43' S.; long. 56° 23' W., 10.5 

 fathoms, east coast South America. 



