Vertebrates require an extensive intestinal surface area in order to absorb sufficient nutrients to sustain growth and development. Amniotes, like humans and chickens, contain a long looping, vilified intestine. The developmental process of villi formation is partially dependent on a constrictive force provided by differentiated circular smooth muscles encasing the proliferating luminal endoderm, causing longitudinal ridges to form. In a later event, formation of longitudinal muscles causes further compression such that a luminal zig-zag pattern arises, and eventually individual villi. The little skate, Leucoraja Erinacea has a relatively short intestine that is internally spiraled to compensate for the loss of surface area that accompanies the loss of length. The internal spiral is covered with villi to further increase absorptive surface area. To determine the role of smooth muscle in the development of the spiral valve intestine, I stained for smooth muscle in the developing spiral valve intestine. Staining revealed that circular smooth muscles surrounding the spiral differentiate prior to helical muscle differentiation within the turns of the spiral. Further characterization is being completed to determine the precise stages and sequence of circular and helical smooth muscle differentiation. In the chick, more so than other amniotes, villus formation is predominantly dependent on constrictive smooth muscle causing tissue buckling. Because of the parallel patterning of smooth muscle and luminal endoderm in the spiral intestine, it is clear that smooth muscle is also important for intestinal function in the skate. Through further stage characterization and experimentation the question of the importance of smooth muscle in spiral formation is being explored.