242 MEMOIRS OF THE UNIVERSITY OP CALIFORNIA 



Gymnodinium paradoxum Scliilling 

 Text figure X, 26 



Gymnodinium paradoxum Schilling (1891o.), pp. 278, 279, pi. 10, fig. 13; (1913), p. 18, 



fig. 15. 

 G. paradoxum., Ludwig (1898), p. 299. 

 G. paradoxum, Mez (1898), p. 216. 



G. paradoxum, Sehoiiic-hen and Kalberlah (1900), p. 231; (1909), p. 252. 

 G. paradoxum, Lemmermann (1900), p. 116; (1902), p. 260; (1903a), pp. 86, 88, 90, 108; 



(19056), p. 159; (1908), pp. 170, 180; (1910), pp. 565, 618, 620, 626, fig. 22. 

 G. paradoxum.. West and West (1906), pp. 91, 92; (1909a), p. 187. 

 G. paradoxum., Klebs (1912), p. 384. 

 G. paradoxum. West (1916), p. 51. 



Diagnosis. — A minute species with a broadly ellipsoidal bod,y, its length 

 1.12 transdiameters ; girdle slightly postmedian, without displacement; sulcus 

 very short; dark browoi chromatophores. Length, 40/^. Fresh water, Scottish 

 and English lakes, German lakes, February to April, near Basel, Switzerland. 



Description. — The body is rotund ellipsoidal, with broad apices, widest in the middle, its 

 length 1.12 transdiameters at the widest part. The epicone exceeds the hypocone in size, its 

 length being greater by 0.27. It is elongated hemispherical in shape, with broad apex. Its 

 length is about 0.57 of the total length of the body. The hypocone is subhemispherical in shape 

 with smoothly rounded antapex. 



The girdle forms a complete circle around the Irody slightly posterior to the midplane. It is 

 rather broad and comparatively shallow. Distinct outlines for the girdle and .sulcus are not 

 given in Schilling's figure (1891a). The transverse and longitudiiuil flagella arise near together 

 at the junction of the girdle and sulcus. 



The nucleus is not figured by Scliilliug. The central part of the cytoplasm is filled with 

 dark brown chromatophores. On tlie ventral side, immediately below the ends of the girdle, is a 

 relatively large, ellipsoidal pigment spot, the color of which is not indicated, tliough presumably 

 of a red color. 



Dimensions.- — Length, 10/^; transdiameter, 34.5a*. 



OcctTERENCE. — It was figured by Schilling (1891^) from fresh-water swamps 

 and ponds near Basel, Switzerland. It is frequently found among vegetation 

 and in the plankton. Other records of its occurrence are as follows: West 

 and West (1909) from the Scottish and English lakes and Lemmermann (1903rt, 

 ]905Z>), in ponds in Germany, from February to April. 



Synonymy. — West and West (1906) mention a variety of this species, G. 

 paradoj'nm var. major, from Lough Currane, Cottuty Kerry, Ireland, named 

 by Lemmermann. The only data given are its length, 66-75/', and transdiameter 

 of 61-67/^. It is not figured. Its position and relationship tints cannot be de- 

 termined, since the j)roportions of length and transdiameter differ from those 

 of G. paradoxum. 



Co:mparisons. — This species is closely related to G. rotund at urn and G. vin'de 

 in the sul)geni;s Gijmnodiniuni, l)ut it is larger and more rotund than these 

 species, differing also from the former in the presence of the eyespot. In size 

 and shape it is near G. uherrinuuii. but the large eyespot and indistinctness of 

 the chromatophores serve to separate it from that species. 



