Animal. Body ovate, somewhat convex above, and divided into two parts transversely; lateral lobes of the foot very thick; head indistinct, and without tentacula; branchiæ placed on the back.
Shell. Concealed in the mantle, very thin, rolled and spiral on one side; without a columella and spire; aperture very large and wide, dilated at the upper part. Inhabits the British seas. Two species.
- Bullæa aperta.
- B. striata.
3. Genus Bulla. Pl. [X].
Animal. Body oblong-ovate, slight convexity; divided into two portions transverse above, mantle slightly folded posteriorly; visible tentacula; branchiæ dorsal and covered, opening only on the right side.
Shell. Univalve, ovate globular, convolute, no columella, spire not projecting but visible, aperture the whole length of the shell, external margin sharp and smooth. Inhabits the British and American seas. Nineteen species.
- Bulla physis.
- B. naucum.
- B. hydatis.
- B. rugosa.
- B. fragilis.
- B. aplustre.
- B. ampulla.
- B. lignaria.
- B. fasciata.
- B. striata.
- B. Wyatii.
- B. solida.
- B. cornea.
- B. lactea.
- · · · · ·
- B. solitaria.*
- B. triticea.*
- B. hiemalis.*
- B. Gouldii.*
- B. lineolata.*
FAMILY V.
Aplysiacea. Two genera.
1. Genus Dolabella. Pl. [X].
Animal. Body creeping, oblong, narrowed in front; and posteriorly widened; area round, sloping, and truncated obliquely; margins folded over the back; four tubular tentacula, disposed in pairs; bronchial operculum inclosing a shell; orifice dorsal, near the branchiæ.