KOPOID AND SWEZY: UNARMORED DINOFLAGELLATA 301 



somewhat above the surface of the body. The sulcus begins near the right side of the apex and 

 extends posteriorly in a slightly sinuous line to the autapex. The anterior flagellar pore opens 

 at the proximal junction of the girdle and sulcus, the posterior pore about one width of the 

 girdle below the distal junction. 



The nucleus is a spheroidal body filled with coarse chromatin strands. It is found near the 

 center or sometimes in the anterior part of the body. Its axis is about 0.5 transdiameter in 

 length. 



A small sacklike pusule opens into each flagellar pore; sometimes one or both may be 

 temporarily absent. In one individual the anterior pusule was located near the center of the 

 body and connected with the anterior pore by a slender canal. The cytoplasm is coarsely 

 granular, often vacuolate in structure with few to many long, greenish rodlets radially arranged. 

 The peripheral zone contains a layer of much smaller, radially arranged, blue-green rodlets 

 placed at right angles to the surface. They appear between the surface striae in surface view as 

 minute, blue-green, circular granules. The surface is longitudinally striate with equidistant, 

 blue-green lines, about 24 across the ventral face of the epicone, and twice as many on the 

 hypocone. The general color of the organism is pale Veronese green with, rarely, a tinge of 

 coral red in the epicone. 



DiMEXsioxs.— Length, 46-57/^; transdiameter, 29-38m; axis of nucleus, 

 13-17/^. 



OccuEREXCE. — This was first observed in two surface hauls made July 18 

 and 19, 1906, one 0.75 mile, the other 1.5 miles off La Jolla, California, with a 

 No. 20 net, and in a surface temperature of 21?9 C. On July 12 and 20, 1917, 

 it was taken in two hauls made with a No. 25 net, 6 miles offshore, from 80 

 meters to the surface and in surface temperatures of 20°6 G and 21-1 C respec- 

 tively. It was again observed August 8, in a haul 4 miles offshore, from 80 

 meters to the surface and in a surface temperature of 22?5 C. 



Other records of its occurrence are as follows: Pouchet (1883) from the 

 Atlantic off Coucarneau, Prance; Levander (1894«-1913), from the Gulf of 

 Pinland near Helsingfors, Piuland; Ostenfeld (1908), from the Aral Sea in 

 May. in surface temperature ranging from 17?7 C to 25?6 C, and Lebour 

 (1917/>), from Plymouth Sound, England, in August and September. 



Syxoxymy. — This was first figured by LcA'ander (1894r?) as Gijnniodiuium 

 fissum and was later changed by Lemmermann (1900) to Spirodiuium fission. 

 In 1908 Paulsen placed with it as synonymous a form figured by Pouchet in 

 1883 as Gymnodinium spirnle var. D. Ostenfeld (1908) records a species from 

 the Aral Sea as Spirodiniion fissnin Levander with a question mark, stating that 

 he was miable to identify it definitely as Levander 's species. His observations 

 were limited entirely to preserved material, and these forms very rarely with- 

 stand contact with a fixing fluid. Miss Lebour 's (1917?;) form from Plymouth 

 Sound, England, is also doubtfully allocated. No figure or description is given 

 save that it is yellow in color with a peculiar dorsoventral flattening. In all 

 of our material the color was green and the bod}^ circular or nearh- so in cross- 

 section. In Levander 's (1894a) description the color is green and the body 

 rounded in vertical view. He ol)served one individual with a slight dorsoventral 

 compression of the body. 



