Case of rugosa spider conch shells wholesale, also referred to as arthritic spider conch, which is popular with shell collectors because of the unique combination of rich purple and orange in the aperture. These rugosa spider conchs measure between approximately 3 inches and 5 inches in length. Lambis is a genus of large sea snails sometimes known as spider conchs, marine gastropod mollusks in the family Strombidae, the true conch family