DINOFLAGELLATA 329 



D. acuta E. (Fig. 133,/). Oval; attenuated posteriorly ;54-94/z long; 

 widely distributed; British Columbia (Wailes). 



Genus Oxyphysis Kofoid. Epitheca developed; sulcus short; sulcal 

 lists feebly developed; sagittal suture conspicuous; annulus im- 

 pressed; salt water (Kofoid, 1926). 



0. oxytoxoides K. (Fig. 133, g, h). 63-68 M by 15/*; off Alaska. 



Family 3 Phytodiniidae Klebs 



Genus Phytodinium Klebs. Spherical or ellipsoidal; without fur- 

 rows; chromatophores discoidal, yellowish brown. 



P. simplex K. (Fig. 133, i). Spherical or oval; 42-50/x by 30-45m 

 fresh water. 



Genus Dissodinium Klebs (Pyrocystis Paulsen). Primary cyst, 

 spherical, uninucleate; contents divide into 8-16 crescentic second- 

 ary cysts which become set free; in them are formed 2, 4, 6, or 8 

 Gymnodinium-like swarmers; salt water. 



Fig. 134. a, Leptodiscus medusoides, X50 (Hertwig); b, Craspedotella 

 pileolus, X110 (Kofoid). 



D. lunula (Schutt) (Fig. 133, j, k). Primary cysts 80-155/* in 

 diameter; secondary cysts 104-130/z long; swarmers 22/x long; widely 

 distributed; British Columbia (Wailes). 



Suborder 3 Cystoflagellata Haeckel 



Since Noctiluca which had for many years been placed in this 

 suborder, has been removed, according to Kofoid, to the second sub- 

 order, the Cystoflagellata becomes a highly ill-defined group and 

 includes two peculiar marine forms: Leptodiscus medusoides Hertwig 

 (Fig. 134, a), and Craspedotella pileolus Kofoid (Fig. 134, b), both 

 of which are medusoid in general body form. 



References 



Allen, W. E.: (1946) Significance of "red water" in the sea. Turtox 

 news, 24:49. 



Balech, E.: (1949) Etude de quelques especes de Peridinium, sou- 

 vent confondues. Hydrobiologia, 1:390. 



(1951) Deuxieme contribution a la connaissance des Peridi- 

 nium. Ibid., 3:305. 



