310 



GRIFFIN. 



bristles can not be said until E. vannus has been reexamined with especial 

 regard to these structures. The same is true of the suboral membranellEe 

 and rows of endoral cilia. 



The j)rincipal specific characters of Euplotes ivorcesteri are the fol- 

 lowing: Body oval, anterior end rounded, posterior end bluntlj' pointed; 

 dorsal surface considerably elevated, with a regular curvature; anterior 

 half of right margin usually .straight; body 72 /i to 93 /t in length, 47 

 /i to 60 /t in width. Ventral surface flat; peristome considerably ex- 

 cavated and broad, extending two-thirds the length of the body, con- 

 taining 45 to 70 wide membranellaj ; mouth irregularly oval, large; 

 pharynx long, recurved, containing 20 to 30 membranellse. several oblique 

 rows of endoral cilia, and a group of suboral membranellas ; 7 frontal 

 cirri, 3 abdominal cirri, o anal cirri, 3 left marginal cirri, 0-3 right 

 marginal or caudal cirri; sensory bristles of the dorsal surface usually 

 in eight longitudinal rows; on the ventral surface paroral, exoral, and 

 lateral rows of sensory bristles, and two to four bristles at the base of each 

 cirrus. Meganucleus long, horseshoe-shaped, with a fluke-like enlarge- 

 ment at the posterior end and a considerable thickening where it bends 

 across the anterior end of the body. Mieronucleus single, lying in a 

 slight depression of the meganucleus, on the left side near the anterior 

 end of the body. 



The dimensions of ten specimens of E. u-orcesieri, selected at random, 

 are : 



Specimen No. 



Dimen- 

 sions. 



Specimen No. 



Dimen- 

 sions. 



1 



Microns. 

 76X47 

 85VfiO 



8 - — - 



9 . - 



Microns. 

 85X60 

 81X56 

 76X51 



82X54 

 72X47 





3 ' n.'ivBn 



10 



4 



5_ _ . 



6 



72X47 

 85X56 

 76X47 

 89X60 



Average .size 







9SV60 









