Habitat: Exclusive of reef habitats, under 5 m deep. Distribution: Bahamas, Belize, Venezuela. Depth: less than 10m Characteristics: Massive amorphous to regularly lobate. Color black to purplish gray externally, tan internally. The sponge skin is very smooth and it wrinkles when lifted out of the water. Consistency compressible and dense, easily torn. Apertures: Oscules on the top of the lobes (diameter 0.5 cm). A tangential setcion at the surface shows the numerous ostia (inhalant pores) regularly scattered on the surface. Skeleton: Spicules are aspidasters , flattened (180-200 μm in length); micro-oxeas to strongyloxeas slightly centrotylote and slightly curved (30-50 x 3-4 μm); tylasters with spines swollen at the ends (approx. 28 μm in diameter); orthotriaenes with short rhabdome (400 μm in lenght) and clads ( approx. 200 μm in length); large oxeas straight or slightly curved (1000 x 20 μm). The surface formed by a well differentiated cortex containing stricly aspidasters, micro-oxeas, tylasters and tangential orthotrianes. Choanosome with bundles of oxeas radially oriented with scattered young aspidasters. Notes: Synonims: Erylus clavatus, Pulitzer Finali, 1986 (WPD). A sister species E. gofflieri (Wiedenmayer, 1977) has a surface pierced by holes. Erylus formosus species have been identified to contain triterpene glycosides which work as antifeedant agents, protecting the sponge from predation.