PLATE XIV. 



DIFFLUGIA UECEOLATA. 



All the figures were taken from living specimens, represented in their usual position, anil with 

 the shells composed of angular particles of quartz sand. 



Fig. 1. Variety approaching Difflugia acuminata. 200 diameters. Swarthmore brick-pond, Dela- 

 ware County, Pennsylvania, October, 1875. 



Fig. 2. Variety with less acuminate fundus to the shell. 250 diameters. Lake of Uinta Mount- 

 ains, Wyoming'. August, 1*77. 



Fig. 3. Varietj Difflugia amplwra. 100 diameters. Ditch below Philadelphia. Common form. 



FlG. 1. Oral view of a similar specimen. 



Fig. 5. Characteristic specimen of Difflugia urceolata. 200 diameters. Absecom pond, New Jersey, 

 August, 187(5. Common form. 



Fig. 6. Narrower variety of the same kind occurring with it. 



Fig. 7. Common form in ditches communicating with the Delaware River below Philadelphia. 



Fig. 8. Common form; abundant in a pond of Bridger Butte, Fort Bridger, Wyoming, August. 

 1877. 250 diameters. 



Fig. 9. Acuminate variety, with additional spines to the fundus. A not unfrequent form. Atco, 

 N. J., September, 1*77. 250 diameters. 



Fig. 10. Common variety. Absecom pond, New Jersey. 250 diameters. 



Fig. 11. Variety named Difflugia oll/i. Abundant in the ponds of Bphagnous swamps. Budd's 

 Lake, New Jersey, September, 1874. 250 diameters. Tin 1 sarcode encysted. 



Fig. 12. Unsymmetrical specimen. Absecom pond, New Jersey, September, 1875. 200diameters. 



Fig. l:>. Many-spined specimen, found with the former. 200 diameters. Each spine ending in a 

 single large sand grain. 



Fig. 14. Single-spined specimen. Atco, N. J., September. 1*77. 250 diameters. The spine end- 

 ing in a single large sand grain. 



