KOFOID AND SWEZY: UNARMORED DINOFLAGELLATA 147 



The nucleus is a small, ellipsoidal body found near the antapex. It is filled with fine chromatin 

 granules. Its major and minor axes are about 0.55 and 0.36 transdiaraeters in length respectively. 

 A spheroidal food mass is usually present near the girdle region. 



Dimensions. — Length, 25m; transdiameter, 11/*; axes of nucleus, 6 and 4/*. 



Occurrence. — Figured by Lohmann (1908) from the Baltic Sea off Kiel in 

 July and August. The only other record of its appearance is that of Schroder 

 (1911) from the Adriatic Sea, near Lucietta off Austria-Hungary, July, in 

 vertical hauls of 100 and 200 meters. 



.Uelationships. — It stands midway between A. lanceolatum Schroder and 

 A. crassum Lohmann (figs. U, 9, 18). Its form suggests Oxytoxum, l)ut there 

 is no indication of a theca. 



Amphidinium operculatum Claparede and Lachmann 



Text figure U, 25 



Amphidinium operciilaium Claparede and Lachmann (1858-61), pp. 410, 411, pi. 20, figs. 



9, 10. 

 A. operculatum, Leuekart (1861), p. 152. 

 A. operculatum. Diesing (1866^), p. AT. 

 A. operculatum, Fromentel (1S74), p. 197. 

 A. operculatum, Maggi (1874), p. 119; (1880), pp. 5, 15. 

 A. operculatum, Saville-Kent (1880-82), p. 461, pi. 25, figs. 45-46. 

 A. operculatum, Bergh (1882), p. 694. 



A. operculatum, Daday (1883), p. 477; (1884), pp. 5, 11, 12. 

 A. operculatum, Entz (1884), p. 239 ; (1896), p. 22; (1904). p. 112 ; (1907), p. 18; (1909), 



p. 255. 

 A. operculatum, Mcintosh (1889), pp. 323, 337. 

 A. operculatum., Balbiani (1894), p. 257, fig. 41. 



A. operculatum, Levander (1894c), p. 210; (1910), p. 41; (1901b), pp. 8, 13, 18. 

 A. operculatum, Clave (1894), p. 10. 

 A. operculatum, Schiitt (1895), p. 92. 



A. operculatum, Tempere (1898), p. 127, pi. 15, fig. 8. Indeterminable. 

 A. operculatum, Florentin (1899), p. 334. 



A. operculatum, Lemmermann (1900V p. 115; (1901), p. 358; (1910), p. 616. 

 A. operculatum, Massart (1901), p. 81. 

 A. operculatum. Calkins (1902), p. 432, fig. 27. 

 A. operculatum, Kofoid (1907a), p. 301. 

 A. operculatum. Cavers (1913), p. 180, fig. 8^, j. 

 A. operculatum, Griessmann (1913), pp. 3, 14. 

 Not Amphidinium operculatum. Stein (1883), Klebs (1884), Biitschli (1885), Schiitt 



(1896), Schroder (1900), Lemmermann (1903), Paulsen (1908), Ilerdraan (1911a, 



19116, 1912, 1913). 



DiAGNOSis.-^A small species with ellipsoidal, dorsoventrally flattened body, 

 its length 1.5 transdiameters ; girdle anterior extending posteriorly on ventral 

 side; sulcus extending from girdle to antapex; yellow lirown chromat()]>liores. 

 Length, 45/*. Coast of Norway, west coast of Sweden, Atlantic oft" A\'oo(ls Hole, 

 Mass. 



