DIFPLUGIA OBLONGA. 



9 



The author of ' Infusionsthierchen ' describes and 

 figures them as distinct, though the incompleteness of 

 his figures of proteiformis leaves it an open question 

 as to what particular form that name was designed for. 

 The uncertainty would have been obviated had the 

 author figured the oral aperture. In that case — if 

 w^e may judge from the general outline — in all proba- 

 bility one of the species with a lobate mouth (e. p. 

 D. lohostoma Leidy) would rightly have borne the 



39 



38 



Fias. 38 AND 39. — Difflugia oblonga : 38, common form incrusted with 

 sand-grains, x 200 ; 39, a peculiar form from Clapham, W. Torks, 

 chiefly incrusted with diatoms, x 310. The latter reduced from 

 a drawing by G. S. West. 



name proteiformis Ehrenb. In any case it cannot be 

 accepted as a synonym for D. oblonga Ehrenb., and 

 the safest course now is to discard the name protei- 

 formis altogether. 



Examples are occasionally met with in which the 

 test is in some degree compressed, and occasionally a 

 want of bi-lateral symmetry is observable (fig. 39) ; 

 whilst others have the croAvn peaked like a Grothic 

 arch. These variations were regarded by Leidy as 



