PLATE XXXVn. 
PAGE 
Figs. 1-8. CVTHERIDEA SUBOVATA n. SP 124 
1. A right valve doubtfully referred to this species. The posterior 
outline is more uniformly rounded and the central portion of 
the surface more peaked than usual. Plum Point. 
2, 3. Interior of a left valve of the normal form x 37 and x 20. 
4, 5. Two left valves of a narrow variety. 
6. Dorsal edge of a typical specimen. 
7, 8. Interior of a right valve of the typical form x 37 and x 20. 
Fig. 9. Cytheridea ( ?) chesapeakensis n. sp 125 
9. A right valve of this species. Plum Point. 
Figs. 10-16. Cytherideis ashermani n. sp 126 
10. Rather large left valve. Surface pitting indistinct. Plum 
Point. 
11. A small right valve. 
12. 13. Two small left valves. 
14. Interior of a large right valve. 
15. Dorsal aspect of an entire carapace tilted so as to show 
more of the left valve than of the right. 
16. A left valve differing from the usual form in being relatively 
a little longer and in having the posterior outline less nar- 
rowly rounded. 
Pig. 17. Cytherideis cylixdrica n. sp 126 
17. A left valve. Plum Point. 
Figs. 18-20. Cy'theriueis semicircularis n. sp 127 
18. An entire carapace from the right side but tilted so as to show 
the dorsal edge of the left valve, the central part of which is 
really overlapped by the dorsal edge of the right valve. 
19. Ventral view of another entire specimen showing that here the 
left valve slightly overlaps the right. 
20. A right valve showing usual outline and surface markings. 
Figs. 21-27. Cytherideis longula n. sp 128 
21-23. Three right valves showing unimportant variations in outline 
and surface ornament. 
24. Ventral edge of an entire carapace. 
25. A left valve. 
26. A right valve, doubtfully referred to this species. 
27. Interior of left valve of typical form. The pits on the sur- 
face of this valve are about as in figure 22 but more dis- 
tinctly impressed. 
Fig. 28. Cytherideis sub-equalis n. sp 127 
28. A specimen preserving both valves showing the right side but 
tilted slightly to expose the ventral overlap of the left valve. 
The rounded holes in each end are the work of some boring 
mollusk or other organism. Plum Point. 
Pigs. 29-33. Cythereis cornuta var. Americana n. var 122 
29. Dorsal view of a left valve. 
30-32. Three left valves showing the extremes of variation observed 
in the Maryland specimens. 
33. A right valve. 
Excepting Pigs. 2 and 7, all the figures on this plate are magnified 20 
diameters. The specimens are all from the Calvert formation at Plum 
Point, Md. 
29 
