PeridiniacesB 65 



margins of the furrow. Only in the Podolampinse is the transverse flagellum 

 exposed on the surface of the wall and not hidden in a groove. It is always 

 turned to the left side of the cell-body. It is in some forms a thread-like 

 flagellum and in others a band-like structure. Its nature is not easily 



Fig. 47. A and B, Ceratium Schrankii Kofoid, x310; A, ventral view; B, ventral view of 

 central part of cell to show contents. C and D, C. gallicum Kofoid, x 250 ; C, ventral 

 view; D, central part of cell to show contents, c/t, chromatophores ; n, nucleus; v, 

 vacuoles. (After Kofoid.) 



determined owing to the difficulty in observing the flagellum in the living 

 cell 1 . The transverse flagellum of Pyrodinium bahamense is described by 



1 In some species of Gymnodinium and Peridinium the thread-like transverse flagellum can 

 be seen vibrating by gently running in a small quantity of iodine solution or a 2 per cent, 

 solution of osmic acid at one side of the cover-glass. Whenever the living organisms come 

 w. A. 5 



