PLATE LXIX. 
PAGE 
Pigs. 1-3. Mesouesma mariana n. sp 285 
1. Exterior of right valve. Cove Point. 
2. Interior of right valve. Same locality. 
3. Interior of left valve. Same locality. 
Figs. 4-6. Ervilia plaxata Dall 285 
4. Interior of left valve. Church Hill. 
5. Interior of right valve. Same locality. 
6. Exterior of left valve. Same locality. 
Figs. 7-9. Mactra clathrodon Lea 286 
7. Interior of left valve. Cove Point. 
8. Exterior of left valve. Same locality. 
9. Interior of right valve. Same locality. 
Fig. 10. Spisula (Hemimactra) delumbis (Conrad) 286 _ 
10. Interior of right valve. Suffolk, Va. 96 mm. (After Dall.) 
X 5/6 
Fig. 11. Spisula (Hemimactra) marylandica Dall 2S7 
11. Interior of right valve. 92 mm. (After Dall.) x % 
Figs. 12, 13. Spisula (Hemimactra) cuktidens Dall 288 
12. Outline of young shell traced from incremental lines on broken 
larger valve. 35 mm. (After Dall.) X 5/6 
13. Hinge-plate of right valve: a, dorsal and e, ventral anterior 
laminae; 6, anterior arm of cardinal tooth; c. ligament scar, 
vi'ithout septum below it; d and f, posterior laminae. 44 mm. 
(After Dall.) 
