bb AMERICAN HYDROIDS. 



Laoinedea dichotoina B. Alder, A notice of some new genera and species of Brit. Hydroid Zooph., Ann Ma" Nat 



Hist., ser. 2, vol. 18, 1856, p. 360. 

 Laomedea dicholoma Alder, Description of 3 new Brit. Zooph., Ann. Mag. Nat. Hist., ser. 2, vol. 18, 1856, \>. 440. 

 Laomedea longmima Aldeh, Cat. Zooph. N.orthumb. and Durham, 1857, p. 31. 



Laomedea longisdina Hincks, Cat. Zooph. South Devon, etc., Ann, Mag. Nat. Hist., ser. 3, vol. 8, 1861, p. 154. 

 Laomedea gelatinosa var ramuhsa Kirchenpaubr, Die Seetonen du Elbmiindung, 1862, p. 18. 

 Laomcdii htiuikxiimi Kirchenpauer, Die Seetonen du Elbmiindung, 1862, p. 23. 



Laomnl.'i IniiijixsiiiKi Alder, Report on Zooph., Trans. Tyneside Naturalist Field Club, vol. 5, 1863, p. 290. 

 Laomahii loiigiasiiiui Alder, Suppl. to Cat. Zooph., Trans. Tyneside Naturalists Field Club, vol. 5, 1863, p. 237. 

 Laomedea dichotoma Allman, Report 33rd Meeting Brit. Ass. Adv. Sci., 1864, p. 412.. 

 Sertularia longissima Allman, Notes on Hydroida, Ann. Mag. Nat. Hist., ser. 3, vol. 14, 1864, p. 62. 

 Laomedea gelatinosa A. Agassiz, North Amer. Acalephse, 1865, p. 82. 



Laomedea longissima Parfitt, Additions to the Zooph. of Devonshire, Ann. Mag. Nat. Hist., ser. 3, vol. 18, 1866, p. 11. 

 Laomedea longissima Alder, Report on Zooph., Nat. Hist. Trans. Northumb. and Durham, vol. 1, 1867, p. 49. 

 Laomedea longissima Alder, Report on Zooph., Trans. Tyneside Naturalists Field Club, vol. 6, 1867, p. 193. 

 Campanularia gelatinosa van Benedbn, Recherches sur la Fauna littorale de Belgique, 1867, p. 148. 

 Ohelia longissima Hincks, British Hydroid Zoophytes, 1868, p. 154. 

 Obelia longissima Norman, Shetland final Dredging Report, vol. 2, 1869, p. 322. 

 Laomedea gelatinosa Hbrklots, Natuurlyke Historio van Nederland, 1870, p. 400. 

 Obelia longissima Allman, Gymnoblastic Hydroids, 1871, p. 169. 

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

 Obelia longissima Verrill, Amer. Jour. Sci., vol. 7, 1874, p. 44. 

 Obelia longissima MclNToaH, Ann. Mag. Nat. Hist., ser. 4, vol. 13, 1874, p. 207. 

 Obelia longissima Clark, Alaskan Hydroids, 1876, p. 212. 

 Obelia longissima Verrill, Check list of Marine Invert., 1879, p. 16. 

 Obelia polystyla Haeckel, Lyst du Medusen, 1879, p. 117. 



Obelia longissima Crawford, Ann. Mag. Nat.. Hist., ser. 6, vol. 16, 1895, p. 260. 

 Obelia longissima Nutting, Hydroids of the Woods Hole Region, 1901, p. 351. 

 Obelia longissima Hargitt, Synopsis N. A. Invert., 1901, p. 383. 



Laomedea longissima Saemundsson, Bidrag til Kundskaben om de islandske Ilydroider, 1902, p. 58. 

 Laomedea longissima Billard, Cent, k I'^tude des Hydroides, 1904, p. 23. 

 Laomedea longissima Hartlaub, Hydroids of Magellan Straits, 1905, p. 582. 

 Laomedea longissima Billard, Exped. Antarctique Franfaise, 1906, p. 11. 

 Laomedea longissima Ritchie, Hydroids of Scottish Nat. Antarctic Exped., 1907, p. 528. 



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

 Obelia longissima Jaderholm, Northern and Arctic Invert., pt. 4, Hydroiden, 1909, p. 63. 

 I^aomedea longissima Broch, Hj^droiden der arktischen Meere, 1909, p. 229. 

 Obelia longissima Mayer, Medusse of the World, vol. 2, 1910, p. 225. 



Trofliosome} — Colony 13.2 cm. in height and consisthig of a central imduhxting stem 

 very dark brown proximally and hghtening distally. Branches alternate and themselves often 

 branching and resembling the main stem m detail. There are usually 3 to 5 annulations above 

 the origin of each branch, branchlet, and pedicel. Pedicels varying considerably in length 

 and sometimes longer than the hydrothecse, annulated throughout. Hydrothecse deeply 

 campanulate, with regularly but slightly curved outlines and the margins armed with very low 

 teeth which are not always evident. 



Gonosome. — The gonangia are borne in the axils of the branches, branchlets, and pedi- 

 cels, shaped like a slender urn or Pompeian water jar, broadening from the base to the shoul- 

 der, where the sides contract to form a short curved neck ending in a small aperture. The 

 gonangial contents are developing medusse, usually a dozen or more appearing in the same 

 gonangium. The medusae have 20 to 24 tentacles when liberated and accordmg to Mayer 

 (1910) can not be distinguished, when mature, from other medusse of this genus. 



Distribution. — This species is common on both sides of the North Atlantic where it extends 

 northward to Iceland (Saemundsson) and Greenland (Levmsen), Arctic Ocean (Jaderholm); 

 and southward to the coast of France (Billard). It has been reported from the New England 

 coast by Verrill and Nutting and from the Pacific coast of Alaska by Clark. Hartlaub reports 

 it from Chile and the Straits of Magellan, Ritchie from Gough Island and the South Orkneys 

 and Billard from the Antarctic. 



Bathymetric distribution, 1 to 80 fathoms. 



Description of a specimen from Plymouth, England. 



