Surface morphology of the ciliary apparatus in the eye of Galago senegalensis.

The folded portion of the ciliary body (pars plicata) in Galago senegalensis consists of a series of processes extending from the flat region (pars plana) over the posterior half of the ciliary muscle to the posterior surface of the iris near the limbus. Each process has an anterior portion (iridial process) that is distinguished by its surface morphology from a posterior portion (ciliary process). Iridial processes attach to the iris and are devoid of zonular fibers, while ciliary processes, although continuous with iridial processes, are covered completely with fibers. The transition from one to the other occurs at a point nearest the lens where zonular fibers leave the ciliary body to transverse the posterior chamber. The innermost margin of both processes is an expanded crest (ciliary crest) running along each shelflike ridge (ciliary ridge). The ridges represent inward projections of the ciliary body forming the mesentery-like membrane of the pars plicata. Zonular fibers take origin from a complex multilayered basal lamina of the ciliary epithelium found in all regions except on iridial processes. The pars plana is covered by longitudinally-oriented fibers, many of which are attached at the retinociliary junction. These zonular fibers converge on the base of ciliary processes, some entering each ciliary cleft to insert on ridges and many others continuing anteriorly over the surface of ciliary crests. The fibers on crests lift away from the ciliary process at its transition with the iridial process and extend to the lens. Other fibers that project to the lens originate on ciliary ridges and make their way onto each crest near this transition and appear to be projecting from ciliary clefts.