KOFOID AND SWEZY: UNAKMORED DINOFLAGELLATA 225 



Gymnodinium lineatum sp. nov. 



Plate 1, figure 2; text figure Y, 14 



Diagnosis. — Large species with ovoidal body, its length 1.7 transdianieters ; 

 girdle siibmedian in j^osition, displaced 0.2 transdiameter ; sulcus extending 

 from the apex to the antapex ; s;u-faee striate ; color, pale green yellow. Length, 

 143/*. Pacific off La Jolla, California, July. 



Description. — This is one of the largest species of Gymnodinium. The body is ovoidal, 

 rounded at both apices, widest anteriorly, its length 1.7 transdianieters at the widest part. A 

 cross-section of the body is nearly circular. The epicone, having a greater width than the 

 hypocone, is slightly larger, though it is exceeded in length by the hypocone by 0.1 of its length. 

 The epicone is irregularly, somewhat asymmetrically rounded with broad apex. It has a length 

 on the left and riglit sides of 0.38 and 0.49 respectively of the total length of the body. The 

 hypocone is much narrower than the epicone, conical in shape, about 50°, the angle increasing 

 slightly near the girdle, with a broad, blunt antapex. Anteriorly it flares out in a wide, shelflike 

 border to the girdle. 



The girdle is submedian in position. Its proximal end joins the sulcus at a distance from 

 the apex of 0.38 of tlie total length of the body. It follows a descending left spiral course 

 around the body and its distal end meets the sulcus at a distance from the apex of 0.49 of the 

 total length of the body, giving it a displacement of 0.2 transdiameter, or about 3 times its own 

 width. The furrow is wide, about 0.05 transdiameter, and deeply impressed with wide, over- 

 hanging shelflike borders. The sulcus begins at the apex and extends posteriorly as a shallow 

 channel. It follows a slightly sinuous course which is deflected to the left posterior to the 

 proximal junction with the girdle, terminating near the left side of the antapex. The anterior 

 flagellar pore is found at the proximal junction of the girdle and sulcus. The posterior pore 

 is about a width of the girdle below the distal junction. 



The cell inclusions consist of nucleus, pusule, vacuoles, small spherules and rose-red coloring 

 material. The nucleus is a large ellipsoidal body in the left central part of the epicone. It is 

 filled with fine,- moniliform chromatin strands arranged along its shorter axis. Its major and 

 minor axes are about 0.47 and 0.3 transdiameter respectively in length. 



A large pusule opens into the anterior flagellar pore. It has an irregular sacklike extension 

 anteriorly and a larger one posteriorly, both branches joining immediately dorsad of the anterior 

 pore. No pusule could be detected in the region of the posterior pore. The cytoplasm is coarsely 

 granular and alveolate in structure. Near the central part of the body is a mass of large, 

 greyish vacuoles and scattered sparsely through the remainder of the body are smaller vacuoles 

 filled with the same salmon-pink fluid found in the jjusules. The general color of the organism 

 is a pale green yellow diffused through the body. 



The surface is marked by equidistant striae, about 25 across the ventral face. These consist 

 of linear series of minute, rod-shaped, blue-green, lenticular bodies. The number is approxi- 

 mately the same on both epicone and hypocone. On the epicone these extend from girdle to 

 apex, diminishing in number as they near the apex. On the hypocone they are deflected postero- 

 sinistrally, following the border of the sulcus on the left side but having a greater obliquity on 

 the riglit, where they extend from the girdle to the right border of the sulcus. 



Dimensions. — Length, 112-143/*; transdiameter, 68/*; axes of nucleus, 34/* 

 and 23/-*. 



OccuREFA'CE. — The first specimen ob.s'crvcd was taken July 14, UJOti, with a 

 No. 20 net in a surface haul 2 miles off La Jolla, California. The individual 

 figured was taken July 26, 1917, with a No. 25 net, 2.5 miles off La Jolla, in a 



