Cephalobrachia bonnevii Massy, 1917
Overview
This is a naked pelagic snail, up to 0.3 cm long, mainly transparent. The posterior footlobe and lateral lobes are small. There are no gills. The hook sacs are very large. It hunts zooplankton as food. It lives in the N-Atlantic Ocean in the upper water layers (Cephalobrachia bonnevii draw).
Taxonomic Description
Body is, similar to Clione, tapering posteriorly. Skin unpigmented. No gills and no ciliary bands around the body in mature specimens. The wings are narrow at their base, but broaden rapidly. Footlobes small, the posterior one is short and pointed. A median foot tubercle is absent. There are no buccal cones or buccal arms. The buccal organs resemble those of the preceding species in general appearance (Cephalobrachia bonnevii). The radula formula is 5-1-5. The median plate is sickle-shaped with three subequal denticles. There are about 20 transverse rows of teeth. There are about 16 hooks at each side in the same shape as in Cephalobrachia macrochaeta.
Body length up to 2.5 mm.
Juveniles
A special description is not available.
Reproduction
This species is a protandric hermaphrodite.
Ecology
This species is carnivorous.
Distribution
The type specimen is from a depth of only 40 fathoms off SW Ireland. This is the only record known, see the Cephalobrachia bonnevii map.
Types
Cephalobrachia bonnevii, Massy, 1917: 237, pl. 8, fig. 4.
Type locality: 52°2'30"N 10°56'W. Coll.: CHCE stat. 529