Part 98

497. Ervillia nitens.

Fam. Corbulacea.

498. Potamomya, of some authors. A fresh-water shell resembling Corbula. Outside, valves closed.

499. Inside of both valves.

Fluviatile Conchacea.

500. Cyclas amnica. Pera, Leach.

Fam. Cardiacea.

501. Cardilia semisulcata. Isocardia semisulcata, Lam. Internal view.

502. External view of the same valve.

503. Cardium apertum. Papyridea, Sw.

504. The same, shewing the umbones.

505. Pleurorynchus, fossil, (from Mineral Conchology.)

Fam. Phyllidiana.

506. Chiton fascicularis. Phakellopleura, Guild.

507. ---- amiculatus. Amicula, Gray.

Fam. Calyptracea.

508. Scutella, Brod. Internal view.

509. External view of the same.

510. Ancylus, a reversed species, illustrating the genus Velletia, Gray. Enlarged view.

511. The same, natural size.

512. Pedicularia. Enlarged figure, (copied from Swainson.)

513. The same, natural size, growing on coral.

Fam. Colimacea.

514. Achatina? octona. Macrospira, Guild.

515. Stenopus cruentatus, Guild. Under side.

516. ---- lividus.

517. Helix, the aperture covered by the epiphragm.

518. Pupa secale, Drap. Abida, Leach.