KOFOID AND SWEZY: UNARMORED DINOFLAGELLATA 359 



the body. Posterior to the anterior tiagellar pore it diminishes rapidly to a narrow band about 

 0.2 transdianieter in width, wliich makes one turn around the body, diminishing distally to a 

 slender point. The anterior portion of tlie hyixieone forms a band somewliat wider than the 

 corresponding part of tlie epieone, and makes one eomph'te turn above tlie distal junction of the 

 girdle and sulcus. Posterioi'ly it is broad and rounded and notched at the left side of the antapex 

 by the distal end of the sidcus. 



The girdle is a descending left spiral with a distance from the ai)ex at its proximal and distal 

 ends of 0.35 and 0.85 respectively of the total length of the body. It makes 2.1 turns around 

 the body and is displaced about 0.88 transdiameter. The furrow has a width of about 0.08 

 transdiameter, narrower distally, and is deeply impressed, undercutting its antei'ior border and 

 curving gradually out to the posterior one. The sulcus scai-cely extends anterior to its proximal 

 junction with the girdle, but continues posteriorly in a descending left spiral of slightly more 

 than one turn and terminates in a notch at the h'ft side of the antapex. It forms a shallow 

 trough with smooth sides, and the width is less tlian half that of the gii-dle. The anterior and 

 posterior pores open at the anterior and posterior junctions of the girdle and sulcus respectively. 



The nucleus is a spheroidal body filled with moniliform chromatin strands and located in the 

 anterior part of the body, dorsad to the anterior pore. Its axis is 0.53 transdiameter in length. 



Small club-shaped pusules open into each flagellar i)ore. In one specimen examined the 

 posterior pusule was seen filling up with a sudden inrush from the outside surrounding medium. 



The cytoplasm is finely granular. In the peripheral zone are numerous, light oriental green 

 rodlets placed perpendicularly to the surface (fig. HH, 12). These are about 7/a in length and 

 arranged quite close together. Inside this zone and longitudinally arranged are about six long 

 slender curved rhabdosomes which persisted when cytolysis had caused the dissolution of the 

 body. Outside of these two regions and in the periphery are numerous blue-green rodlets with 

 larger patches of the same color, quite closely scattered through the peripheral plasm. 



The color is an amber yellow shading down to an orange tint at the antapex. A few large 

 patches of yellow color are found near the apex and equatorial region. 



Dimensions. — Length, 35—49/^; transdiameter, 25-32/*; axis of nncleus, 

 13-15/*. 



OccuRREXCE. — This was one of the species most freqtiently taken, oecnrring- 

 in most of the liauls made between Jnly 12 and August 21, 1917, from distances 

 11,6. and 4 miles off La Jolla, California, in hauls from 80 meters to the surface 

 and was also found in the surface hauls taken at the end of the pier at the 

 Biological Station. The forms figured came from the hauls made at the last 

 named point. 



Comparisons. — This species belongs to the C. citron group of the subgenus 

 Cochlodinium, characterized by two complete turns of the girdle. It stands 

 closest to C. clarissinmm (fig. GC, 2), without, however, having the aj)ical loop 

 of the sulcus and the superficial vacuolate zone of the latter species. In its 

 peripheral zone of radial rodlets it recalls the condition in many of the species 

 of Gyrodinium. 



Cochlodinium clarissimum s]). nov. 



Plate 5, figure 60; lext figure GG, 2 



Diagnosis. — A medium sized species with rotund ellipsoidal body, its Icnglli 

 1.51 transdiameters ; girdle a descending left spiral of 2 turns, displaced 0.76 

 transdiameter; sulcus with apical loop and torsion of 2 turns; (»olor. ]inl(' 

 glaucous green. Lengtli, 59/'. Pacific off La Jolla, Califoi-nia, July. 



