The Morphology of the Pecten Oculi and the Conus Papillaris

Abstract

In this study, the pecten of the house finch, and the conus of the gecko, Eublipharis, were utilized. The structure of the house finch pecten resembled that of the pigeon. The capillary endothelium is characterized by an extensive luminal and abluminal system of plasma membrane plications (Fig. 1, LP and AP). The luminal ridges vary in length from 1.3 - 2.9μ, and are 40-90 mμ in width. The luminal and abluminal plications are separated by the narrow, rather dense endothelial cytoplasm which contains free ribosomes and dense mitochondria in addition to granular cytomembranes. The abluminal ridges are generally shorter, and rest on a basement membrane. Many of the pecten surface capillaries are separated from the vitreous by only a short distance of about 1μ. In other regions the capillaries are surrounded by pigmented cells, which contain smooth surfaced, very osmiophilic granules up to 1.6μ in diameter, a few smaller, irregularly shaped granules and the usual compliment of cytoplasmic organelles (Fig. 2).In sharp contrast to the pecten, the endothelium of the conus is relatively smooth and lacks any surface foldings as well as any fenestrations (Fig. 3). The endothelial basement membrane is separated from that of the pigment cell by a variable extracellular connective tissue space containing many collagen fibrils. The pigment cells contain melanin granules similar to those of the pecten (Fig.4).