DIFFLUGIA OBLOXGA. 11 



from which it may be distinguished by the sub- 

 cylindrical lower portion of the test. 



Var. claviformis (Penard). (Plate XVII, figs. 6 and 9.) 



Difflugia pyriformis LEIDY (pars) Fresliw. Rhiz. N. Amer. 

 p. 98, t. x, f. 16. 



Difflugia acuminata LEIDY (pars) Freshw. Rhiz. N. Amer. 

 p. 109, t. xiii, ff. 3, 4. 



Difflugia pyriformis var. claviformis PENARD in Rev. Suisse 

 Zool. VII, 1 (1899), p. 25, t. ii, ff. 12-15; Faune Rhiz. 

 Leman (1902), p. 219, ff. 3, 4 (p. 218) ; andSarc. grands 

 Lacs (1905), p. 19, f. (p. 20); AVERINTZEV in Trudui 

 S.-Peterb. Obshch. XXXVI (1906), 2, pp. 198, 201; 

 SCHOUTEDEN in Ann. Biol. Lacustre, I, 3 (1906), pp. 342, 

 346 ; THIEBAUD & FAVRE in Ann. Biol. Lacustre, I, 3 

 (1906), pp. 76, 82; SCHNEIDER in Arch. Biontol. II, 1 

 (1908), p. 57. 



Test large, comparatively smooth, opaque, sub- 

 pyriform, the crown obtusely angular or terminated 

 by a conical protuberance, the sides swelling outwards 

 to the broadest diameter, thence curving downwards 

 to the truncated mouth. Nucleus normally situated ; 

 the pseudopodia thick, blunt, branching from a mass 

 of granular protoplasm issuing from the mouth of the 

 test, sometimes knotted. 



Dimensions :. Length of test 390-435 p. ; breadth 

 1 30-200 /x in broadest part. 



Pond at Chelford, Cheshire. Pond at Chipperfield, 

 Herts (A. Earland). 



Penard describes and figures two forms of this variety 

 one (length 435 /u,) with the crown tapering from the 

 broadest diameter on each side convexly upwards to 

 the obtuse apex ; the other and smaller form (390 ^c) 

 with the apex rounded but terminating in a mamillary 

 protuberance. The two forms occur together at 

 Chipperfield, but having regard to the difference of 

 outline, as well as of size, they might reasonably be 

 regarded as distinct, the larger being true claviformis. 



