Cross section of a cilium showing the 9 + 2 axoneme. Two dynein arms, inner and outer, of heterogeneous appearance arise from the complete microtubule of each doublet. Spokes extend from the doublets toward the central pair. Other densities extend from the central pair and between some of the outer doublets and the membrane. A heavy glycocalyx (polysaccharide coat) is found on the outside of the ciliary membrane as well as the plasma membrane. TEM taken on 2/3/69 by R. Allen with Philips 300 operating at 60kV. Neg. 47,100X.