Clipped Semele Shell, Semele decisa

Furrow Shells of the Semelidae Family are medium to large size clams that generally have a rounded oval outline and only somewhat inflated. The posterior end is marked with folds or furrows. They have a strong internal ligament that is contained in a compartment just behind the small cardinal teeth. The exterior of the shells is usually smooth or sculpted with heavy concentric ridges. Many Semeles are brightly colored.

Semeles reside over and with sand and mud substrate and they possess long siphons that allows them to bury themselves fairly deeply. They are deposit feeders consuming organic material that has settled on and into the sediment. Semeles are capable of movement within the sediment, but seldom move far. They are preyed on by crabs, fish, and shorebirds.

Most Furrows are found in shallow, tropical seas, but some range into temperate or deep water. There are sixty species in the Semelidae Family of which twenty-eight are found along the coastlines of the Baja Peninsula.