PLATE XVII. 



DIFFLUGIA COEONA. 



All the figureB were from living specimens ; the shell composed of angular quartz sand and the 

 sarcode colorless. 200 diameters, except 'whon specially indicated. 



Fig. 1. Individual with extended pseudopods ; the shell with seven spines to the 'fundus, of which 

 five are visible in the lateral view. The month was furnished with twelve points or teeth and as many 

 Intervening sinuses. The somewhat palmate pseudopods were spread outwardly on the inclined border 

 of a glass cell. A common form in Swarthmore brick-pond, Delaware County, and iu ditches below 

 Philadelphia. 



Figs. 2-4. Common forms, from Lake Hattacawanna, Morris County, New Jersey, October, 1874. 



Fig.-2, lateral view of an individual with extended pseudopods ; shell with seven spines to the 

 fundus and fifteen teeth to the mouth. 



Fig. 3. Inferior view of another individual, exhibiting the month and extended pseudopods. 

 Shell with seven spines to the fundus .ind fourteen teeth to the mouth. A.similar specimen, 0.248 mm. 

 high and 0.24 mm. broad, had seven spines to the fundus and twelve teeth to the mouth. 



Fig. 4. Upper view of a specimen with eleven spines to the fundus. Mouth O.IC mm. in diameter 

 with sixteen brown teeth. 



As represented in the figures, while the body of the shell is colorless, the spines and border of the 

 mouth are frequently stained of a ferruginous brown. 



Figs. 5, 6. Two views of the same individual ; fig. .5, lateral view, with extended pseudopods, and 

 four spines to the fundus ; fig. 6, inferior view exhibiting the mouth with fifteen teeth. Ditch below 

 Philadelphia, September, .1875. 



Fig. 7. Lateral view of a specimen with an oblique mouth as in Difflugia constrkta, bnt furnished 

 with twelve teeth, and having a single spine to the fundus. The only specimen of the kind seen. 

 Swarthmore brick-pond, March, 1875. 



Fig. 8. Inferior view of a specimen exhibiting the mouth with six teeth. The fundus of the 

 shell had seven comparatively short spines. Jacksonville, Fla., March, 1875. 



Fig. 9. Liiteral view of a slightly unsymmetrical specimen with a single spine to the fundus. 

 The mouth had twelve teeth. Ditch below Philadelphia, September, 1875. 



Fig. 10. Lateral view of .an individual with a pair of widely divergent spines to the fundus, and 

 with extended pseudopods. Mouth with twelve teeth. With the preceding. 



Fig. 11. An unusually unsymmetrical specimen. Lateral view with extended pseudopods. Seven 

 spines to the fundus and sixteen .teeth to the mouth. Atco, N. J., September, 1877. 



Fig. 12. Six-lobed mouth of a specimen which had seven spines to the fundus. The shell was 

 0.33 mm. in di.ameter. Lake Hattacawanna, New Jersey. 



Fig. 13. One of the spines ii-om the same specimen, showing a liince-head-Uke flake n.t the end. 

 375 diameters. 



Fig. 14. Three teeth from a specimen like that of tij;. 6, showing terminal colored sand grains. 



