. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Till-: LIGHT-RECEPTIVE ORGANS OF BARNACLES. 539 by all authors studying the Cyprid. In such preparations the eye appeared as consisting of a black pigment body and eight to ten globules or lenses surrounded by a large capsule, and is described as such by Darwin (1851). Hesse (1874), and Von Willemoes- Suhm (1876). When studied in section the compound eyes of I-iahnius balanoldcs (Fig. 2) are found to be situated in pockets near the bases of the antennules. In contrast to the rather unique structure of the median eye, their a
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Till-: LIGHT-RECEPTIVE ORGANS OF BARNACLES. 539 by all authors studying the Cyprid. In such preparations the eye appeared as consisting of a black pigment body and eight to ten globules or lenses surrounded by a large capsule, and is described as such by Darwin (1851). Hesse (1874), and Von Willemoes- Suhm (1876). When studied in section the compound eyes of I-iahnius balanoldcs (Fig. 2) are found to be situated in pockets near the bases of the antennules. In contrast to the rather unique structure of the median eye, their appearance is very similar to that of the compound eyes of other Crustacea. The eight to ten lenses described for similar forms by early authors are present and represent the same number of visual elements or oinmatidia. Each ommatidium contains a cuticular lens surrounded by " cor- neagen cells," which are reported by Patten (1886 and 1887) to FIG. 2. Diagrammatic drawing of the compound eye in the cyprid stage (vertical section X 300). c., cornea; corneagen cells; /., lens; ;/., nerve. secrete this body, and other cells known as the cells of the crystal- line body. The lens or crystalline body is made up of three units forming an egg-shaped structure. The proximal portion of the ommatidium contains the rhabdomes surrounded by heavily pig- mented retinular cells. This region is much shorter in the com- pound eyes of Balanus than in most Crustacea. It was not pos- sible to study the rhabdome in detail but it appears to be like that of other Crustacea, of reticular nature and penetrated by nerve fibrils. The retinular cells pass into the optic nerve of the com-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Marine Biological Laboratory (Woods Hole, Mass. ); Marine Biological Laboratory (
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
