Part 99

519. ---- pagoda. Gonidomus, Sw.

520. Truncatella, enlarged figure.

521. The same, natural size.

522. Auricula caprella. Gen. Caprella, Nonnul. Front view.

523. The same, dorsal view.

524. Pupina vitrea.

526. ---- antiquata.

527. ---- Namezii.

528. ---- lubrica. Callia? Gray.

529. Cyclostoma, a pupiform species. Megalomastoma, Guild.

530. ---- Planorbulum. Cyclotus, Guild.

531. ---- a similar species, with the complicated notch at the posterior part of the aperture. Pterocyclos, Gray.

532. Helicina acutissima, nobis. View of the under side. Trochatella, Sw.

533. The same in profile.

534. } } 535. } Strophostoma, Desh. three views. } 536. }

Fam. Peristomata.

537. Paludina impura. Bithinia, Gray?

538. Ampullaria avellana. Thallicera, Sw. Ampullarina?

539. A species of Ampullaria having a thickened ledge on which the shelly operculum rests. Pachystoma, Guild. changed to Pachylabra, Sw.

Fam. Plicacea.

540. Ringicula, Desh. A fossil species, front view.

541. Back view of the same.

Fam. Turbinacea.

542. Turbo nicobaricus. Chrysostoma, Sw.

543. Trochus Iris. Elenchus, Humph.

Fam. Purpurifera.

544. Purpura vexilla. Gen. Vexilla, Sw.

545. Priamus. Achatina priamus, Auct. The propriety of placing it in this family will depend upon the correctness of the statement made by Dr. Beck that this shell is marine, and possesses an operculum.