Mollusca have chalky shells, except octopus and sea slugs, a wide range of color and shell pattern, often a yellow fleshy body and no obvious body segments. Species include Octopus, Snails, Sea Slugs, (Nudibranchs) and Bivalves.
SNAILS and SLUGS (Class: Gastropoda)
Snails and slugs have internal gills and although present, the shell is usually reduced and often enclosed by the mantle.
SEA HARE (Aplysia depilans)
The sea hare is a gastropod and normally lives among weeds in shallow water. They can often be seen swimming with what appear to be wings. They have four head tentacles, the rear pair are large and resemble the ears of a hare. When mature they reach 25cm long and brown green in color, sometimes with white spots, younger specimens are a reddish brown color. If threatened they sometimes eject a harmless purple dye.
TRITON (Charonia nodifera)
This mollusc is a carnivorous predator preying on starfish and other slow moving animals. They have a large cone shaped spiral shell up to 20cms in length colored brown yellow orange, matching to some extent their habitat among rocks and weed over which they are fairly mobile. They have two very distinctive retractable pointed black and yellow banded head antennae branching out in front of their eyes
MEDITERRANEAN CONE SHELL (Conus Mediterraneus)
This species of a familiar mollusc can be found in shallow sandy bays in great numbers during July and August. It has a short siphonal canal and a long slit like opening with a straight, sharp outer edge. They have a single sharp, venomous hollow tooth which they flick out to inject their prey or in defense if they are threatened. If mishandled by divers the venom can cause varying levels of pain. Fortunately the Mediterranean species are not as poisonous as their tropical relatives.
There are many species of cowries of varying sizes and colors. Their most distinctive feature is the long slit like opening running from end to end and a very smooth outer surface. In life the animal extends a thin mantle over the exterior of their shell and this is the reason why these shells are so smooth and have such a slippery feel. If they are disturbed the cowrie quickly withdraw their mantle into their shell, emerging very slowly when no longer threatened.
GIANT TUN SHELL (Dolium galea)
Normally found in deeper water this mollusc often burrows beneath the surface of the sand with only a small part of its round shell visible. They feed on relatively large slow moving organisms like sea cucumbers, which they ingest whole. The disproportionate volume of their prey often makes it impossible for them to retreat into their shell, and is the reason why they seek protection by burrow themselves into the sand. Empty shells, sometimes up to 150cms in diameter, can often be found in less dived areas.
NUDIBRANCHS (Order: Nudibranchia)
These often highly colored Opisthobranchs lack a shell, have obvious naked gills and a pair of head tentacles. The gills and tentacles are retracted quickly into the body if they are disturbed or threatened.
Many small species of nudibranch exist in Turkish waters. Particularly common is a bright violet colored species which can often be seen clinging to seaweed or marine plants with its fragile appendages waving even in the slightest of currents. Another common variety to be found clinging to rocks or to the surface algae is (Peltodoris atromaculata), which has a flat oval light cream colored body with dark brown patches. Generally between 1cm to 4cm in length they can occasionally reach up to 6cms long, there are two unbranched head tentacles and 9 branching gills in a ring on the back.