KOFOID AND SWEZY: UNARMORED DINOPLAGELLATA 371 



Dimensions. — Length, 45-54/^; transdiameter, 31-35/^; axes of nucleus, 

 15-20m and 12/* ; diameters of fvst, 50/^ and 53/^. 



Occurrence. — Two individuals \Yere taken July 27, 1917, 4 miles off La 

 Jolla, California, in a haul from 80 meters to the surface and in a surface 

 temperature of 21 ?9 C. It was also present August 15 in a haul 0.75 mile 

 offshore, from 70 meters to the surface. 



It was described by Pouchet (1887) from the Atlantic off Concarneau, 

 France, where it was abundant from April 29 to May 3. It has also been 

 recorded from Plymouth Sound, England, by Lebour (Wllh) in August. 



Synon y:\iy. — Figured by Pouchet (1887) as Gymnodinimn helix, the name 

 was changed by Lemmermann (1899) to Coclilodininm helix. Sehiitt (1895) 

 figures under the Gymnodiniam helix Pouchet two distinct forms. His figures 

 111--., plate 24, agree in all essential details with Pouchet 's species. His figure 

 77o, however, is distinct in shape, torsion, and formation of the posterior end of 

 the body. Both of these forms we have found in our material at La Jolla, 

 and have no difficulty in separating them. His figure 776 we therefore reject 

 from Cochlodininm helix and place it in our new species, C. schuetti. 



Comparisons. — This species, like C. cavatum sp. nov. (fig. HH, 10), shows 

 the greatest extent to which the mobility of the posteroventral portion of the 

 Ijodv is developed in this genus. It probably lies in the direct line of evolution 

 which has produced Frotcrijthropsis, and ErytJiropsis (fig. T) with this region 

 of the body still further differentiated in the tentacular recess and the tentacle 

 or prod. It belongs ])etween C. convolutum (fig. HH, 5) and C. cavatum (fig. 

 HH, 10) , as shown by the degree of asjTumetry of the body. 



Cochlodinium lebourae sp. nov. 



Plate 2, figure 23 ; text figure HH, 7 



Diagnosis. — A small species with ellipsoidal l)ody, its length 1.66 transdiam- 

 eters; girdle a descending left spiral of 1.7 turns, displaced 0.83 transdiameters ; 

 sulcus wdth apical and antapical loops, and torsion of 1.5 turns; color, pale 

 lumiere green. Length, 50/*. Pacific off La Jolla, California, July. 



Description. — The body is elongate, subellipsoidal, contracti^d posteriorly, somewhat con- 

 stricted by the girdle, nearly circular in cross-section, its length 1.66 transdiameters at the widest 

 part below the middle. Both apices are broad, the anterior rounded, the posterior notched by 

 the sulcus. The epicene is considerably larger than the hypoconc, its length being greater by 

 0.23 of itself. It is elongate hemispherical in shape with a length from the proximal and distal 

 ends of the girdle of 0.3 and 0.84 respectively of the total length of the body. Its posterior 

 portion consists of a narrow band tapering to a slender jwint distally. The hyi)ocone is more 

 irregular in shape and consists of a wide band which makes slightly more than one turn around 

 the body and a rounded distal portion which is broadly excavated on the ventral surface by the 

 distal end of the sulcu.s. The most posterior segment of tlie hypocone is only 0.6 of the width 

 of the one above it. 



The girdle is a descending left spiral of 1.7 turns ami ii displacement of 0.83 transdiameter. 

 The proxinuil and distal portions of its spiral form angles of about 10° with the transverse plane, 



