308 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



G-yrodinium glaucum (Lebour) 



Plate 9, figure 94 ; text figure DD, 16 

 Spirodinium glaucum Lebour (19176). p. 196, fig. 13. 



DiAGXOSis. — A small species with Ijroadly fusiform body with abruptly con- 

 tracted apices, length 2.46 transdiameters ; girdle far posterior, a descending 

 left spiral, displaced 0.26 of the total length ; sulcus extending from the girdle 

 to the antapex; color, greyish green. Length. iOj^. Pacific off La Jolla, 

 California, July; Phinouth Sound, England, May to October. 



Desckiption. — This is a small species with fusiform body which tapers abruptly at both 

 apices, nearly circular in cross-section, its length 2. ■46 transtiiameters at the widest part. The 

 girdle is placed far posteriorly, making the epieone occupy the larger portion of the body. The 

 epieone has a length on the left of 0.67 and on the right of the sulcus of 0.9 of the total length of 

 the body. The left side is more convex than the right. The apex is pointed and flexed to the 

 left with a resulting rounding up of the right side. The hypoeone is very short and rounded, 

 abruptly tapering to the antapex, which is pointed and slightly excavated on the left side by the 

 distal end of the sulcus. 



The junction of the girdle and sulcus occurs at about 0.67 of the total length of the body 

 from the apex. It passes around the body in a descending left spiral course and becomes dis- 

 placed posteriorly on the right side about 0.64 transdiameter, of which the greater part occurs 

 in the last third of its course. On the left side the girdle is wide, about 0.1 transdiameter. and 

 in the last fourth of its course it narrows until at its di.stal end it is about 0.3 of its width at its 

 beginning. It lies in a deep depression with smooth overhanging sides. The anterior flagellar 

 pore is located at the proximal junction of the girdle and sulcus, the posterior pore at the 

 distal one. 



The sulcus is nearly straight, invading the epieone for a short distance anterior to the 

 proximal end of the girdle and extending posteriorly to the antapex. It is relatively wide at 

 its anterior end and becomes narrow near the antapex. 



The nucleus is large and is located in the epieone. It is nearly spheroidal in outline with an 

 axis of about 0.76 transdiameter. It is filled with moniliform cliromatin strands lying obliquely 

 to the longitudinal plane of the body. 



The cytoplasm is clear and hyaline, pale greenish yellow in color. It is nearly filled with 

 hyaline spherical granules, oil droplets and refractive bodies. There are also present 4 to 5 

 long, slender, tapering, yellowish green rodlets, about 0.5-0.66 of the total length of the body in 

 lengtli. These are parallel and are arranged longitudinally near the periphery of the body. 

 They are probably products of metabolism, nutrition being holozoic. The surface is sparsely 

 striate with longitudinal, equidistant striae, about 10 across the ventral face. 



Di:mexsioxs. — Length, 40/*; transdiameter, 16m; nucleus, 12m and 13m. 



OccuERF.xcE. — This was figured by Lebour (1917?0 from Ph^no^lth Sound, 

 England, where it was present from ]May to October. A single individual of 

 this species was met with July 17, 1906, in a surface haul taken with a No. 8 

 net, 1.5 miles offshore, at San Diego, California, and in a surface temperature 

 of 21?9 C. 



Activities. — The specimen under observation was restless, in constant 

 motion, usually moving in a flat, anticlockA\dse spiral direction with a radius 

 not to exceed twice its own length. The ventral surface was usually kept 



