156 MEMOIKS OF THE UNIVERSITY OF CALIFORNIA 



Amphidinium vasculum sp. nov. 



Text figure U, 27 



DiAGxosis. — A rather large species with siibcuueiform body, its length 1.54 

 trausdiameters; girdle without displacement; sulcus short on epicone, reaching 

 antapex on hypocone; color, bright green mixed with pink and yellow orange. 

 Length, 94^^. Pacific, off La Jolla, California, August. 



Description. — The body is rotund, subcuneiform, broadly rounded posteriorly, conical an- 

 teriorly, where is also its widest part; its length is 1.54 trausdiameters at the widest part. A 

 cross-section of the body is nearly circular in outline. The epicone occupies a relatively small 

 part of the body. Viewed from the ventral face it is rhomboidal in shape, with its greatest 

 length equal to 0.4 of the total length of the body. Dorsad, the length of the epicone is 0.13 of 

 the total length. Its general shape is that of a broad, tlat cone of 122° with blunt apes, and 

 nearly straight sides. The hypocone is elongate cylindrical, flaring somewhat anteriorly and 

 broad, smoothly rounded posteriorly, a trifle longer at the left. 



The girdle joins the sulcus at a distance from the apex of 0.4 of the total length of the body. 

 It immediately turns anteriorly at an angle of about 50° with the longitudinal axis of the body, 

 with a slight irregularity in its course, until it reaches the dorsal side of the body, which it 

 traverses in an almost transverse direction at a distance from the apex of 0.13 of the total length 

 of the body. On the right side of the ventral face it again turns posteriorly at an angle of 55° 

 and meets the opposite end of the sulcus without displacement. The furrow is wide, about 0.05 

 transdiameter, and deeply impi-essed, undercutting its anterior border and curving gradually 

 outward posteriorly. Both lips are smooth and flare slightly beyond the surface of the body. 

 The sulcus begins about midway between its junction with the girdle and the apex and extends 

 posteriorly to the antapex. Its course on the epicone is at an angle of about 25° with the longi- 

 tudinal axis of the body. Beyond the girdle its course is that of a straight line to the posterior 

 margin of the body. Posterior to the anterior flagellar pore it becomes slightly narrower than 

 on the epicone, broadening at its posterior extremity. The anterior flagellar pore is located at 

 the junction of the girdle and sulcus, the posterior pore about midway between that and the 

 antapex. 



The nucleus is a rather large ovoidal body lying slightly posterior to the central part of the 

 hypocone. Its axis is about 0.44 transdiameter in length. A small sacklike pusule opens into 

 each flagellar pore. The cytoplasm is finely granular and shows a distinct line of ectoplasm 

 around the margin of the body. This is clear and devoid of alveoli or other markings. In the 

 central part of the cytoplasm, slightly posterior to the anterior flagellar pore, is a dark, spheroidal 

 body, ventrad to which is a group of minute, bright green refractive granules. These immedi- 

 ately surround the anterior flagellar pore and its communicating pusule. Radiating out from 

 this center are a number of long, blue green rodlets or canals. Near both apices are groups of 

 large, salmon pink vacuoles. A few blue green oil droplets and one large, olive green body and 

 one of yellow ochre near the midregion complete the list of cytoplasmic inclusions. The general 

 color is bright green mixed with pearl grey, pink and yellow orange. No striae or other surface 

 markings could be detected. 



Dimensions. — Length, 94m ; transdiameter, 61/* ; axis of nucleus, 28/*. 



OcciTERENCE. — This was found August 6, 1917, in a haul 4 miles off La Jolla, 

 California, with a No. 25 net, from 60 meters to the surface and in a surface 

 temperature of 21-2 C. It was observed again on August 13, in a haul 0.75 mile 

 offshore and from 83 meters to the surface. 



