This is the Tower Shell (Turritella communis), also known as the Common Tower Shell. It is a medium-sized marine gastropod (sea snail) commonly found on soft sediments in subtidal zones. The shell is tall, slender, and conical, resembling a little tower. It is typically brownish-yellow to white, often with spiral ridges wrapping around the shell.

Location:
Found across the eastern Atlantic — from the coasts of Norway down through the British Isles and into the Mediterranean and North Africa.

Average Size:
Typically about 30 mm long and 10 mm wide, though individuals can reach up to around 50–60 mm in length in some areas.

Family:
Turritellidae (Tower Shells)

Species:
Turritella communis

Shell Description:
The shell is high-spired and sharply pointed, with many whorls stacked in a tower-like form (commonly 16–20 whorls). Surface texture usually includes spiral ridges or beaded bands. The opening (aperture) is small and angular, and the snail has a small circular operculum (a little “trapdoor”) sometimes fringed with fine bristles.

Habitat:
Common on soft seabeds such as muddy or sandy sediment. It usually lives partly buried and often rests at a slight angle (about 10°). It occurs from shallow sublittoral waters down to depths of around 200–220 metres.

Feeding:
The Tower Shell feeds by a combination of ciliary suspension feeding and deposit feeding: it filters very small organic particles from the water with cilia on its gills and also ingests fine organic material from the sediment.

Movement and Behaviour:
It moves slowly using a small muscular foot and often remains partly buried in the seabed. In suitable soft-sediment areas these snails can occur in large numbers, although they do not form dense beds like mussels.

Ecological Role:
By feeding on suspended and sedimentary organic particles, Tower Shells help recycle nutrients in the seabed and contribute to sediment turnover. Empty shells often provide shelter and substrate for other small marine animals, supporting local biodiversity.

Reproduction:
Male and female individuals are separate. Fertilisation involves direct transfer and is followed by the release of planktonic larvae (trocophore and veliger stages) that drift in the water before settling and developing into juveniles.

Conservation Status:
Common and widespread in suitable habitats and not considered threatened overall. Local declines may occur where seabed habitats are damaged or heavily disturbed.