KOFOID AND SWEZY: UNARMORED DINOFLAGELLATA 333 



G. spiralc, Schilling (1891), pp. 200, 205, 206. 



G. spirale, Whitelegge (1891), pp. 181, 188, pi. 28, fig. 8. 



G. spiralc, Sehiitt (1895), pp. 33, 37, 95, 113, 117; as Spirodinium spirale (1896), p. 5, 



fig. 6. 

 G. spirale, Delage and Herouard (1896), p. 384, fig. 666. 

 G. spirale, -Jorgensen (1899), p. 26. 



Spirodinium spirale, Leiamermann (1899), p. 339; (1901), p. 358; (1902), p. 260. 

 S. spirale, Schroder (1900), p. 13; (1911), pp. 620, 626, 651. 

 8. spirale, Pavillard (1905), p. 47. 

 Gymnodinium spirale, Dogiel (1906), pp. 40, 41, 43. 

 G. spirale, Karsten (1907), p. 335. 



Spirodinium spiraJe, Paulsen (1907), p. 24; (1908), pp. 101, 102, fig. 140. 

 Gymnodinium spirale, Prance (1908), p. 48. 



G. spirale, Doflein (1909), p. 461, fig. 412; (1911), p. 527, fig. 472^. 

 . G. spirale, Herdman (19116), p. 72; (1911c), p. 40. 

 Spirodinium spirale, Schiller (1912), p. 28. 

 S. spirale, Cavers (1913), pp. 182, 183, fig. 9,,. 

 S. spirale, Ostenfeld (1913), pp. 123, 338, 344, 476. 

 S. spirale. West (1916), p. 51, fig. 36c. 

 S. spirale, Lebour (1917&), p. 193, fig. 10a. 



Diagnosis. — A medium sized species with fusiform body, its lengtli 2.5 trans- 

 diameters ; girdle a descending left spiral, displaced 1.19 transdiameters ; sulcus 

 extending from apex to antapex ; surface striate ; color, ivory yellow. Length, 

 105m to 150ft. Cosmopolitan marine habitat. 



Description. — The body is slender fusiform, widest po.steriorly, tapering anteriorly, nearly 

 circular in cross-section, its length 2.5 transdiameters at the widest part. The dorsal side is 

 convex, the ventral subeoncave, giving both apices a slight ventrad deflection and the whole body 

 a small degree of asymmetrj^, which is most noticeable in lateral view. The greatest length of 

 the hypocone is somewhat less than that of the epieone, but its size is greater, due to its con- 

 tinuously greater trausdiameter. The epieone has the shape of a cone of about 40°, convex ou 

 the left and dorsal sides and becoming concave on the right and ventral sides. The apex is blunt. 

 It has a length on the left and right sides of 0.3 and 0.76 respectively of the total length of the 

 body. The sides of the hypocone are subparallel anteriorly, rounded posteriorly, deeply notched 

 on the left side of the antapex by the distal end of the sulcus, with the right side forming a 

 rounded lobe extending 0.19 transdiameter beyond the left. 



The girdle is a steeply descending left spiral with a displacement of 1.19 transdiameters or 

 0.47 of the total length of the body. Its proximal ciul joins the sulcus at a distance from the 

 apex of 0.3 and its distal end 0.76 of the total length of the body, with an overhang of about 

 0.19 transdiameter. The furrow has a width of about 0.08 transdiameter and is deeply impressed 

 with smooth borders which are generally undercut and somewhat elevated above the surrounding 

 surface. The sulcus extends from the apex to the antapex with a torsion of about 0.19 trans- 

 diameter. Its width is about half that of the girdle in the intercingular area, narrower anteriorly 

 and widening somewhat posteriorly where it excavates the left side of the antapex. The anterior 

 flagellar pore opens at the proximal junction of the girdle and sulcus, the posterior i)ore about 

 one width of the girdle below the distal junction. 



The luicleus is ellipsoidal to spheroidal in shajx' and is situated in the anteroeentral jtart of 

 the body. It is filled with fine moniliform, subparallel chromatin strands. Its major and minor 

 axes are about 0.47 to 0.71 (to 0.56 transdiameter in the spheroidal form) in length. 



Small sacklike ])usules may be present at either pore or at both. In the individual figured 

 thf |)osterior pusule was very large and the anterior one absent. The eytopla.sm is very finely 



