PLATE XIV. 



DIFFLUGIA URCEOLATA. 



All the figures were taken from living specimens, represented in t'ueir usual position, and with 

 tlie shells composed of angular particles of quartz sand. 



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

 ware County, Pennsylvania, October, 1875. 



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

 ains, Wyoming, August, 1877. 



Fig. 3. Variety Difflugia amphora. 100 diameters. Ditch below Philadelphia. Common form. 



Fig. 4. Oral view of a similar specimen. 



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

 August, 1876. Common form. 



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



Fig. 7. Common form in ditches communicating with the Delaware Eiver 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 uot unfrequent form. Atco, 

 N. J., September, 1877. 250 diameters. 



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



Fig. 11. Variety named Difflugia oUa. Abundant iu the ponds of sphagnous swamps. Budd's 

 Lake, New Jersey, September, 1874. 250 diameters. The sarcode encysted. 



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



Fig. 13. Many-spined specimen, found with the former. 200 diameters. Each spine ending in a 

 single large saud grain. 



Fig. 14. Single-spined specimen. Atco, N. J., September, 1877. 250 diameters. The spine end- 

 ing in a siugle large sand grain. 



