PLATE XIII. 
Cucuttma (continued). 
FIGS, 
1—3. (. nana, Leym. Gault, Folkestone. British Museum, No. L 4946. 
(P. 62.) 
1. a, left valve; b, dorsal of same; c, same x 2; d, left x 2; e, anterior view x 1}. 
(The umbo is slightly pressed in, and consequently in 1a, d, appears less sharp 
than usual.) 
2. Right valve x 2. 
3. Left valve ; the posterior margin is slightly imperfect. » 13. 
A, 5. C. Mailleana (d’Orb.). (P. 63.) 
4. Chalk Marl, Pinhay Cliffs. Collection of C. J. A. Meyer. a, left valve; 0, same, 
x 14; c, same, dorsal, x 14. 
5. Chloritic Marl, Maiden Bradley. Woodwardian Museum. With the shell partly 
removed. a, right valve; 6, dorsal of same specimen. 
6. C.,sp. Chalk Marl (Bed 10), Dunscombe. Collection of C. J. A. Meyer. 
a, right valve ; b, dorsal outline; ¢, ornamentation x 4. (P. 64.) 
Genus Isoarca, Minster. 
7. I. Agassizi, Pict. and Roux. Cambridge Greensand (derived). Internal 
mould. Figured by Jukes-Browne. Woodwardian Museum. 
a, left valve; b, dorsal. (P. 65.) 
8. I. obesa (VOrb.). Chloritic Marl, Ball Wood. Museum of Practical 
Geology, No. 6349. a, left valve; b, dorsal; c, ornamentation 
>< Da (lem (8)9))) 
Genus PEcruncuuus, Lamarck. 
9, 10. Pectunculus marullensis, Leym. Ferruginous Sands, Shanklin. Collec- 
tion of C. J. A. Meyer. (P. 66.) 
9. Left valve. a, x 2; 6, interior; ec, dorsal outline. 
10. Left valve x 3 (another specimen). 
