S. cornuta forms encrusting colonies that are pink to salmon in color. Zooids are oval to hexagonal and measure approximately 0.35 X 0.25 mm in size. Heavy calcification between zooids obscures distinct boundaries between individuals. The frontal surface is perforated by many tiny pores that become more irregular in shape as the colony ages due to secondary calcification. The orifice is semicircular with 2 cardelles and a proximal V-shaped sinus. Avicularia are elliptical and may be single or paired. They are raised on processes inferior and lateral to the orifice, and generally have their mandibles pointed upward at a 45-degree angle.