354 MEMOIRS OF THE UNIVERSITY OP CALIFORNIA 



AcTrvTTiES. — Tliis is an active organism, moving in loose circles in an anti- 

 clockwise direction with rotation on its major axis in a clockwise directon, 

 reversing occasionallv. 



^to 



Cochlodinium augustum sp. nov. 



Plate 5, figure 53 ; text figure HH, 15 



Diagnosis. — A large species with fusiform body, its length 2.3 transdiam- 

 eters; girdle a descending left spiral of 4.1 turns, disjilaced 0.74 total length; 

 sulcus with short apical loop, torsion 3.1 turns; color, gi-eenish grey with a 

 tinge of salmon pink ; holozoic. Length, 108/*. Pacific off La Jolla, California, 

 August. 



Description. — The body is sj'mmetrically fusiform, elongated, deeply constricted by girdle 

 and furrow, its length 2.3 transdiameters at the equator. The epicoue very slightly exceeds the 

 hypocone in size. Its length at the proximal and distal ends of the girdle is 0.14 and 0.88 

 respectively of the total length of the body. The apex is asymmetrically rounded, deflected to 

 the left and only slightly grooved on the ventral surface by the shallow ascending loop of the 

 sulcus. The hypocone has a length of 0.86 and 0.12 respectively of the total length at the 

 proximal and distal ends of the girdle. The antapex is flattened hemispherical in form, fur- 

 rowed ventrally by the distal end of the sulcus, but is without a sulcal notch in the postmargin. 



The girdle leaves the sulcus 0.14 of the total length of the body from the apex. It sweeps 

 around the body in a descending left spiral of 4.1 turns before joining the sulcus distally at a 

 point distant from the antapex 0.12 of the total length of the body. It forms a fairly uniform 

 spiral deflected 20° from the horizontal except at the two ends where it is flattened almost to 

 the horizontal. It lies in a deep depression throughout its course and has high overarching 

 borders. The lips are smooth, with a green line along its anterior side. Its width is 0.09 trans- 

 diameter. The anterior flagellar pore is located at the anterior junction and the posterior 

 flagellar pore at the posterior junction of the girdle and sulcus. The transverse flagellum was 

 very .short in the individual figured, traversing scarcely 0.5 turn of the girdle. The longitudinal 

 flagellum is about half the length of the body in length. 



The sulcus invades the hypocone a short distance, forming a shallow, slightly curved loop 

 terminating near the apex. Below the pore it follows the course of the girdle midway between 

 its turns, reaching the posterior junction of the two after 3.1 turns. It lies in a narrow deep 

 depression and is a slender trough 0.5 the width of the girdle. Beyond the pore it traverses 

 the hypocone vertically for a short distance as a deep trough terminating near the antapex 

 without sulcal notch. 



The nucleus is an ellipsoidal body centrally located, its major axis nearly coinciding with 

 the short axis of the body. Chromatin threads could not be found in its very transparent 

 substance. Its major and minor axes are 0.5 and 0.3 transdiameter respectively in length. 



A large club-shaped pusule opens anteriorly into the anterior flagellar pore and a slightly 

 smaller one posteriorly into the posterior pore. The cytoplasm is granular. A few small blue- 

 green oil globules were present, one group in the anterior part of the body and another group 

 below the midregion, all near the girdle. In addition there were three groups of pink vacuoles 

 in the peripheral plasm, two along the left margin and a third of four nnich larger, ellipsoidal 

 vacuoles near the antapex. One large, spheroidal, greenish food mass was located near the 

 nucleus. Near the apex is a group of slender, sharp-pointed, greenish rhabdosomes or rodlets 

 arranged longitudinally near the proximal end of the girdle at the left of the main axis. The 

 color is a mixture of grey, blue green, and salmon pink, the last strongest around the border of 

 the body. No surface markings or striations were observed. 



