KOFOID AND SWEZY: UNARMORED DINOPLAGELLATA 305 



Comparisons. — This species is close to Gjjrodinmm nielo sp. nov. (fig. CC, 9), 

 but is smaller, stouter, with less of an apical point, less displacement of girdle 

 and torsion of sulcus with no overhang. The presence of chromatophores differ- 

 entiates it definitely from Gyrodiniiim, ovoideum sp. nov. (fig. CC, 6), a larger 

 species without apical point but with alioixt the same proportions. 



Gyrodinium fucorum (Kiister) 

 Text figure EE, 3 



G]/mnorliiiiinii fiirorum Kiister (1908), pp. 352-356, figs. 1-4. 



G. fucorum, Kofoid (1909), p. 246. 



G. fucorum, Entz (1910), p. 161. 



G. fucorum, Pavillard (1910), p. 536. 



G. fucorum, Jollos (1910), pp. 181-193, pis. 7, 8. 



G. fucorum, Giinther (1911), p. 8. 



G. fucorum, Hartmann (1911), p. 16, fig. 4. 



G. fucorum. Senn (1911), p. 639. 



Description. — A small species with rotund ellipsoidal body and broad apices, its length 1.33 

 transdiameters at the widest part ; the girdle a descending left spiral, its relations to the sulcus 

 unknown. The epicene exceeds the hypocone in size. The color is pale yellow. Kiister 's ( 1 908 ) 

 outline figures give the outline only of the cell, omitting all cell contents. 



Dimensions. — Length, 28-85m; transdiameter, 60-()5m. 



Occurrence. — This was figured by Kiister (1908) from the North Sea off 

 Helgoland, Germany. He was alile to keep it in cultures of sea water in the 

 laboi'atory for six months. 



Synonymy.— Under the name Gi/mnodi)iiiiiii fiicontiti Kiister (1908) has 

 figured a form with a spiral girdle which evidently belongs to Gjirodimmn. 

 His figitres and diagnosis, however, are entirely inadequate to establish its 

 species characters, giving as he does the merest outline of the body and omitting 

 the full course of the girdle and its relations with the sulcus. 



Jollos in 1910 published the results of his studies of the same material, which 

 he olitained from Kiister. Unfortunately he does not add to our knowledge of 

 the species characters of this form beyond stating that the girdle forms a steep 

 spiral. This character wotdd remove it from Gymnodinium., where he leaves it, 

 l)ut is sufficient only to locate it in the genus Gyrodinium. He describes division 

 which takes place within the cyst and results in four- or eight-celled stages 

 (Kiister, 1908). He also figures swarm spores, l)ut does not show any con- 

 necting link between them and the dividing Gy)iniodiitiniu. The later devel- 

 opment of the swarm spores was not followed. It is possible that he is here 

 confusing two entirel}^ different organisms. His figures 30-41, ])late 8, are 

 those of a small flagellate belonging to Bodo or Proirazekin, having a nucleus 

 with a central karyo.some, a paraliasal body or large blei)haroplast and two 

 unequal flagella, one of tliem trailing. This divides by a simple mitosis with 

 a small niunl^er of clu'oiiiosoincs, unlike the type of mitosis found in Gymno- 

 dinium. Tliere appear, therefore, fundamental differences between his two 



