386 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



9.59-9.62 as compared with 0.64. Its proportions are much stouter, its length 

 lieing 1.4 transdiameters as compared with 2.25. It differs from C. conspimtum 

 (tig. GG, 10) in lieing nearly twice as long, haA'ing 0.50-0.62 instead of 0.9 

 turn in the torsion of the sulcus, and in possessing a longitudinal instead of a 

 transverse antapical loop. 



The nature of the large vacuolated structi;re interpreted by us a food mass 

 is x^rohlematical. In the nmnber and regularity of the vacuoles it is unlike 

 other food masses. There is, however, no such regularity in these structures 

 as appears in the nuclei of Amoehophrija parasitic in Sticholonche (see Bor- 

 gert, 1897), and there is no motion in the structure such as we have deserved 

 in this parasite in PoncJietia. The interpretation of the structure as a parasite 

 thus appears to be excluded. The presence of the mass inside of a vacuole, and 

 the concentration of vacuoles about it, suggest a food mass in a rapid phase of 

 intracellular digestion. In case this is the correct interpretation, the similarity 

 of the mass in size, location, and condition in all of the individuals can be 

 explained only on the basis of the captui-e of the same t^-i^e of food at about 

 the same interval prior to observation on the part of all of the four individuals 

 observed. This is a sufficient number of instances to suggest selective feeding 

 on the pai't of the organism. The nature of the food could not be determined. 

 Its shape and size do not agree with any known dinoflagellate. The presence 

 of a nucleus recognizably of the dinoflagellate type in one instance indicates that 

 the food may be one of the many small and as yet undescribed dinoflagellates 

 which occur in the plankton. 



Cochlodinium virescens sp. nov. 



Plate 9, figure 104; text figure HH, 11 



Diagnosis. — A medium sized species with ellipsoidal, nearly symmetrical, 

 deeply constricted body ; its length 1.5 transdiameters ; girdle a descending left 

 spiral, displaced 0.8 transdiameter ; sulcus with torsion of 0.9 turn ; color, yel- 

 lowish green. Length, 54^. Pacific off La Jolla, California, July, August. 



Description. — The body is ellipsoidal in outline with broad, rounded apices, nearly circular 

 in cross-section, its length 1.5 transdiameters at the widest part at the middle. When first 

 confined under the cover glass the body is generally deeply constricted by the sulcus and girdle, 

 but stiU subsymmetrical, rounding out after being kept for some time under the microscope. 

 Tlie epicone and hypocone are subequal in size. The epieone is subliemispherical in shape, 

 sometimes slightly flattened at the apex or notched at tlie left side by the anterior end of the 

 sulcus. Its length from the proximal and distal ends of the girdle is 0.2 and 0.74 respectively 

 of the total length of the body. Its distal portion forms a wide band which makes about 0.9 

 turn around the body. The hypocone is subhemispherical in shape with broadly rounded or 

 more or less deeply notched antapex. 



The girdle is a descending left spiral with a distance from the apex at its ju-oximal and 

 distal ends of 0.2 and 0.7-4 respectively of the total length of the body, and its displacement is 

 0.8 transdiameter. The major part of its posterior descent takes place in the middle third of 



