NOTES ON DINOFLAGELLATES. 25 



The above description agrees closely with, that given by 

 Kofoid in his monograph, " The Free-living Unarmored 

 Dinoflagellata " (1921). As that description was taken from 

 one of the figures in the L.M.B.C. Eeport for 1911 (this species 

 has not yet been found on the Calif ornian coast), some of his 

 measurements are omitted as being hard to verify and liable to 

 great variation, and the shape and position of the nucleus, 

 which were then unknown, have been added here. 



Amphidinium Jclebsi, Kofoid. A few specimens have been 

 seen from time to time, usually associated with A. herdmani. 



Description. Body elliptical, dorsoventrally com- 

 pressed. Length about 1*7 transdiameters. Epicone small 

 and tongue-shaped, and deflected to the left. Hypocone 

 broadly ellipsoidal, subtruncate anteriorly, rounded posteriorly, 

 its sides sub-parallel for the middle third of their extent. 

 Girdle broad, its ends meeting without displacement. Sulcus 

 extending from the girdle nearly to the antapex. The trans- 

 verse flagellum, arising on the left ventral side, and extending 

 completely round the neck-like girdle to the right ventral side, 

 and often projecting well beyond its borders, so as to be 

 visible throughout its length from the ventral side. Posterior 

 flagellum extending beyond the antapex for a distance probably 

 about equal to the total body length. 



Nucleus large and spherical, situated in the posterior half 

 of the hypocone. Small spherical body similar to that which 

 occurs in A. herdmani occupying the centre of the hypocone. 

 From it slender radiating chromatophores of a pale yellow 

 ochre colour extend towards the periphery. Length 40 to 50/<. 



This description differs from that given by Kofoid, from 

 Klebs's figure, in the arrangement of the chromatophore and the 

 course of the transverse flagellum. If, however. Klebs's figure 

 be taken as a dorsal view, then the description given differs from 

 his specimens not in tin- course of the transverse flagellum 

 but in the side to which the tongue-like epicone is deflected. 



