1914] Sharp: Diplodinium ecaudatum 75 



right to left. Thus these two circles, although continuous, run in 

 opposite directions. In general the arrangement of the inner and outer 

 lips and the inner and outer furrows is the same as in the case of the 

 dorsal zone. The following differences, however, are to be noted. 

 The outer lip (o. ador. lip, figs. A, B; pi. 3, figs. 1, 2) forms an almost 

 complete circle, the plane of which is not horizontal but inclined pos- 

 teriorly on the left side, and is therefore much higher on the right 

 side. This lip reminds one of a stiff collar which is a little higher 



D. 



■•ador. m. 



■ o. ador. lip 



Fig. A. Anterior view of the oral region of Diplodinium ecaudatum to show 

 peculiar recurved arrangement of adoral membranelles and oral cilia. X 1150. 

 ador. m., adoral membranelle ; D., dorsal side; i. ador. lip, inner adoral lip; o. ador. 

 lip, outer adoral lip; or., oral opening or cytostome; or. cil., oral cilia; or. disk, 

 oral disk; V., ventral side; X, beginning of the adoral row of membranelles; 

 Y, the point at which the adoral row of membranelles becomes recurved upon 

 itself to form the row of oral cilia. 



on one side than on the other and the ends of which do not quite meet 

 in front — the "front" in this case being on the left dorsal side, i.e., 

 just above the left extremity of the dorsal membranelle zone. The 

 inner adoral lip {%. ador. lip, fig. A; pi. 3, figs. 1, 2) is at first invisible, 

 but gradually rises above the edge of the outer lip on the ventral side, 

 and on the right and dorsal sides shows prominently above the outer 

 lip. This inner lip might also be likened to a stiff collar, but in this 

 case the two ends overlap, the terminal end passing internal to the 

 origin, where it may end gradually and indistinctly as in Figure A, 



