PLATE XXIV. 



Figs. 1-10.— NEBELA CARINATA. 



Fig. 1. Broader lateral view of a living individual, with protruded pseudopods, and shell com- 

 posed of thin plates of variable shapes. Fig. 2. Outline of the narrower side view. Fig. 3. Transverse 

 section with outline of the mouth. Sphagnum of Absecom, N. J., June, 1877. 250 diameters. 



Fig. 4. Broader lateral view of au individual in which the sarcode is of greater proportionate 

 extent thau in the preceding, and the shell composed of plates of varied shapes has also a few particles 

 of sand attached — a rare occurrence in any species of Nebela. Absecom, October, 1874. 350 +. 



Fig. 5. Individual with sarcode contracted into an. oval ball, and throat of shell closed by a lami- 

 nated operculum. The shell composed of thin angular plates. Sphagnum, Swarthmore, Delaware 

 County, Pennsylvania, June, 1877. 250 -f. Breadth of shell, n.108 nun. by 0.04 mm. 



Fig. 6. View of one-half of the broader side of an empty shell, composed of round and oval plates 

 of very unequal sizes. Absecom, N.J. Shell, 0.088 mm. by 0.036 mm. 500-f-. 



Fig. 7. More highly magnified view of a portion of the same under a different focus. 



Fig. 8. View of one-half of an empty shell with a comparatively narrow carina ; the shell com- 

 posed of large oval plates, with small and mostly circular ones in the intervals. Absecom, N. J. 350 +. 



Fig. 9. View of one-half of the broader side of an empty shell with a wide or deep carina ; the 

 shell composed mostly of minute round plates, intermingled with linear plates and a few large oval 

 ones. Absecom, N. J. 350 -f. 



Fig. 10. Empty shell, with broad keel, composed of chitinoid membrane incorporated with scat- 

 tered particles of sand, etc. Absecom, N. J. 100 diameters. 



Figs. 11, 12. -NEBELA COLLARIS. 



Fig. 11. Empty shell, composed of chitinoid membrane, incorporated with thin angular silicious 

 plates, separated by narrow iutervals. Sphagnum, Vinelaud, N. J., September, 1870. 250 diameters. 

 A similar specimen found on Broad Mountain, Pennsylvania, with shell 0.1 mm. long, and 0.068 mm. by 

 O.OJ mm. broad. 



Fig. 12. Empty shell composed of thin, irregular, angular silicious plates in close juxtaposition. 

 500 diameters. Breadth of shell 0.064 mm. by 0.02 mm. This and the preceding form are transitional 

 to the compressed variety of Difflngia pyriformU. 



Fig. 13.— NEBELA HIPPOCREPIS. 



An empty shell, with inflected hollow, spur-like processes ; the shell composed of circular over- 

 lapping plates. Absecom pond, New Jersey, September, 1876. 250 diameters. 



Figs. 14-17.— NEBELA BARBATA. 500 diameters. 



Fig. 14. Broader literal view of an individual, the shell nearly replete with the sarcode and with 

 projected pseudopods. The entire surface of the shell hirsute. Sphagnum water, Absecom, Septem- 

 ber, 1875. 



Figs. 15, 10. Two views of an individual, with the sarcode withdrawn into the body of the shell. 

 Same locality. 



Fig. 17. Individual with the sarcode contracted into a ball, and with the neck of tin' shell occu- 

 pied with discharged exerementitious matter. Same locality. 



Figs. 18, 10.— NEBELA. 



Fig. 18. An empty shell, the broader lateral view, reversed, composed of circular plates of un- 

 equal size. Intermediate in character to Nebela barbata and Nebela collaris, being shaped like the former, 

 but without cils as in the latter. Absecom, N. J., April, 1875. 500 -f-. 



Fig. 19. An empty shell nearly like the former. China Lake, Uinta Mountains, Wyoming Ter- 

 ritory, August, 1877. LOO -f . 



Figs. 20-25.— QUADRULA SYMMETRICA. 



Fig. 20. Lateral view of a living individual. Around the base of the sarcode there were numorous 

 detached plates like those of the shell. Pond at Viueland, N. J., September, 1876. 500 -f-. 



FlGS. 21,22. Two empty shells. Absecom pond, N. J. 500 -f-. 



Fig. 23. Empty shell. Ditch on the Schuylkill, above Manayunk, Philadelphia, April, 1877. 



Fig. 24. Plates of a similar shell highly magnified. 



Fig. 25. Broader lateral view of an individual in which the sarcode is contracted into an oval 

 discoid ball, and the mouth of the shell is closed with a thick laminated operculum. The plates of the 

 shell arranged in a much more diagonal course than usual. Sphagnum, Absecom, N. J., October, 1874. 

 350 diameters. 



