Colony encrusting, unilamellar; autozooids hexagonal to rectangular with frontal wall perforated by circular pseudopores except centrally; orifice with proximal border almost straight; sinus moderate to deep; ovicell globose, imperforate.
(Ramalho et al., 2011)
Arthropoma cecilii is an encrusting bryozoan that forms extensive white or silvery patches varying in size and shape. The colony is composed of a single layer of autozooids. Autozooids are hexagonal to rectangular and longer than they are wide.
Arthropoma cecilii is a warm temperate to tropical species with a circumtropical distribution in regions of the southeast Atlantic (Brazil), western Atlantic, Mediterranean, Indian and Pacific Ocean. In the eastern Atlantic it reaches its northern limit around the Channel Islands, the western mouth of the Channel and off south Cornwall.
The species is able to colonise hard substrates, especially shells and other biogenic carbonates. It occurs in offshore waters and has been reported from 30-80 m in the Mediterranean and on rock at 5 m in Brazil.