PLATE XVII. 



FIGS. 



1-3 a. Difflugia oblonga Ehrenb. (p. 4) Figs. 1, 2. Forms 

 commonly met with in ponds. x 200. Fig. 3. 

 Large form, with a comparatively smooth test, from 

 a pond at Chipperfield, Herts. x 160. Fig. 3 a. 

 Pseudopodia of the same when emitted after irrita- 

 tion, x 160. 



4, 5. D. oblonga var. venusta (Penard) Cash. (p. 10) Forms 

 varying in shape and size. Northenden, Cheshire. 

 x 280. 



6. D. oblonga var. claviformis (Penard) Cash. (p. 11) 

 Large form, from pond at Chipperfield, Herts, x 

 160. 



7,8. D. oblonga Ehrenb. (p. 7) Fig. 7. A very small 

 form, with tubular neck, from pond at Chelford, 

 Cheshire. Fig. 8. A form with a mamillary pro- 

 tuberance on the crown, otherwise agreeing with the 

 type. Pond at Northenden, Cheshire. x 280. 

 9. D. oblonga var. claviformis ? A form varying in the 

 character of the crown, from pond at Chipperfield. 

 x 160. 



