KOFOID AND SWEZY: UNARMORED DINOPLAGELLATA 311 



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

 with smooth sides. The sulcus extends but a short distance on the epicone and posteriorly it 

 fades out a short distance beyond its distal junction with the girdle. It turns towards the left 

 posteriorly with a torsion of about 0..5 turn. The anterior flagellar pore is found at the anterior 

 junction with the girdle, the posterior pore at the posterior junction. 



The nucleus is spheroidal in shape and is located slightly above the central portion of the 

 body. It is filled witli coarse, moniliform chromatin strands. Its axis is about 0.66 transdiameter 

 in length. 



A large sacklike pusule opens into the anterior flagellar pore. The cytoplasm is clear and 

 transparent and contains many large blue-green oil drops, and dark refractive granules. In the 

 individual figured a large, green food mass was enclosed in a food vacuole, evidence of holozoie 

 nutrition. The surface of tlie body is striate with numerous, equidistant, blue-green striae, about 

 equal in number on the hypocone and epieone, 18 to 20 across the ventral face. The color is a 

 deep lichen green with tones of pearl grey. The whole organism has a' highly refractive, glassy 

 appearance. 



DiMEXSioxs. — Length, 38/' ; transdiameter, 18m ; diameter of nucleus, 12/*. 



OcCFRBENCE. — A single individual was taken July 13, 1917, with a No. 25 

 net, 1.25 miles off La JoUa, California, in a haul from 50 meters to the surface 

 and in a surface temperature of about 20?1 C. 



Activities. — It was in constant motion under the microscope, moving in 

 large circles counterclockwise, without rotation. 



CoiMPAEisoxs. — This species presents certain similarities in its girdle and 

 sulcus arrangement to G. ochracciim (pi. 7, fig. 76; fig. DD, 17), having the 

 same amount of torsion but a slightly greater relative degree of displacement. 

 It differs from that species in its smaller size, greenish color and lack of pig- 

 ment, the possession of which is one of the most striking characteristics of 

 G. ochraceum. In size and proportions it is near G. viridescens sp. nov. (fig. 

 DI). 11), whicli has a much smaller epicone, and lacks the posterior torsion of 

 the sulcus. 



Gyrodinium hyalinum (Schilling) 



Text figure CC, 15 



Gymnodinium hyalinum Schilling (1891), pp. 60, 61, pi. 3, fig. 14; (1891&), pp. 199-208, 

 pi. 10, figs. 1-22; as Spirodiuium hyalinum. (1913), p. 21, fig. 2. 



G. hyalinum, Ludwig (1898), p. 299. 



G. hyalinum, Mez (1898), p. 216. 



G. hyalinum, Zacharias (1899), p. 111. 



G. hyalinum, Schoniehen and Kalberlah (1900), p. 231; (1909), p. 252. 



Spirodinium hyalinum, Lemmermann (1900), p. 116; (1903), p. 260; (1910), pp. 565, 613, 

 627, figs. 24, 27, 31. 



Gymondinium hyalinum Entz, Jr. (1902), p. 125; (1907), p. 17; (1909), p. 254. 



G. hyalinum, Wesenberg-Lund (1904), p. 107. 



G. hyalinum, Ruttner (1906), p. 6. 



G. hyalinum, Dogiel (1906), pp. 32, 40. 



G. hyalinum. Klebs (1912), pp. 391, 429, 430. 



Spirodinium hyalinum. West (1916), p. 53, fig. 36c. 



