184 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



The girdle is slightly postmedian, its distance from the apex being 0.5 of the total length of 

 the bodj\ It forms a complete circle around the body. The furrow is about 0.1 transdiameter 

 in width and deeply impressed with overhanging borders. The sulcus begins midway between 

 the girdle and the apex and extends posteriorly in a straight line to or near the antapex. The 

 transverse and longitudinal flagella both arise near together at the junction of the girdle and 

 sulcus. 



The nucleus is a spherical body near the apex. Its diameter is about 0.2 transdiameter of 

 the body. Numerous blue green ehromatophores fill the peripheral zone of the cytoplasm and 

 give their color to the organism. 



Dimensions. — Length, 33-34j^; transdiameter, 21-22^^; diameter of snlcns, 5/^. 



OcciTEREXCE. — Figtired by Stein (1883) from fresli-\Yater ponds near 

 Chodan. Austria. Other oeourrenoes reported are as follows: Levander 

 (1894fl) from several lakes in Finland and (1894?;) near Helsingfors, Finland; 

 Bntsehinsky (1897) at Odessa, Enssia; Amberg (1900) at Zm-ich, S\\-itzerland ; 

 Marsson (1901) near Berlin, Germany; Euttner (1906) near Prag, Austria; 

 KolkTvitz (1911) eastern Eussia and western Germany; Entz (1896) in Hun- 

 gary : Zenker (1912) near Hildesheim, Germany; and Klebs (1912) near Buiten- 

 zorg, Java. 



Klebs's (1912) record of the occurrence of this species in the tropical waters 

 of Java may be held as tentative, since he gives no figures or description. The 

 change from the cool temperate regions of Finland and Germany to the tropical 

 waters of Java, about 15° C, might be expected to residt in specific differences. 



Co:mparisoxs. — This species is closely related to G. palustre and G. viride 

 in size, form, and habitat, and is one of a small groitp of fresh-water species, 

 most of them possessing brownish or greenish ehromatophores and of an 

 elongated, subovoidal form, alwut 1.5 transdiameters in length. This species 

 differs from all others of the group in having bluish green, ellij)tieal, disklike 

 ehromatophores. 



Gymnodinium agile sp. nov. 



Plate 3, figure 31 ; text figure Y, 9 



DiAGxosis. — A minute species with body rounded disklike, its length 1.07 

 transdiameters, with sinistral apical point; girdle median, withoitt displace- 

 ment; sulcus extending from girdle to antapex; colorless, with orange green 

 ehromatophores. Length, 28/^. Pacific off La Jolla, California, Jidy, August. 



Descriptiox. — The body is rounded in ventral view, fiattened dorsoventrally. with broad 

 apices, its length 1.07 transdiameters at the widest part, its dorsoventral diameter 0.4 of its 

 transdiameter. The epicone and hypocone are siibequal. The epieone is subhemispherieal with 

 the apex displaced to the left as a minute, pointed, finger-like projection bending downward 

 towards the surface of the body. The length of the epicone is about 0.5 of the total length of 

 the body. The hypocone is sjTnmetrically hemispherical in ventral view, with the antapex 

 occasionally notched by the distal end of the sulcus. 



The girdle is equatorial in position and is without displacement, forming a complete circle 

 around the body. The furrow is broad, about 0.08 transdiameter, and deep with smooth, 



