Abstract
This study describes the electron microscopic features of protrusions on the intestinal circular muscle surface of Artemia nauplius larvae and adults. The distribution, thickness, and form of the protrusions changed with the growth and those of the adults were thicker, forming a bundle of fine protrusions. The budding form of the protrusion from the circular muscle surface was observed, and junctions were detected both at the parts in contact among the protrusions and the connection between the protrusion and the circular muscle cell. These results suggest that the network of protrusions allows communication among circular muscle cells.
