. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. ANATOMY OF THE TUNICATE TADPOLE 13 • i. FIGURE 11. Electron micrograph of cross-section through the center of the prosencephalon. A = photoreceptor axons, DPC = dorsal melanocyte, EP = epidermis, LC = lens cell, PR = photoreceptor cells, V = ventricle, VPC = ventral melanocyte. Bar = 10 jum. scriptions of the tadpole of the tunicate Amaroucium constellatum, and see Dilly and Wolken [1973] for a description of the ocellus of adult dona. Eakin [1973] and Salvini-Plawen and Mayr [1977] provide comprehensive general discussions
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. ANATOMY OF THE TUNICATE TADPOLE 13 • i. FIGURE 11. Electron micrograph of cross-section through the center of the prosencephalon. A = photoreceptor axons, DPC = dorsal melanocyte, EP = epidermis, LC = lens cell, PR = photoreceptor cells, V = ventricle, VPC = ventral melanocyte. Bar = 10 jum. scriptions of the tadpole of the tunicate Amaroucium constellatum, and see Dilly and Wolken [1973] for a description of the ocellus of adult dona. Eakin [1973] and Salvini-Plawen and Mayr [1977] provide comprehensive general discussions of the evolution of visual organs.) Yet another striking cell type characterizes the prosencephalon. A group of gen- erally fusiform cells (4-5 ^m wide) in the left ventro-caudal wall of the ventricle protrude tubulated bulbs (1-2 /^m in diameter) into the ventricular lumen (Fig. 12). Each bulb sits on a ciliated stalk (9 + 0), and the axoneme runs up one edge of the bulb just inside the cell membrane. The remainder of the bulb is packed with generally parallel arrays of short membranous tubules with a fairly uniform diameter of /urn. The cytoplasm of the cell bodies is slightly more granular than the cytoplasm of the surrounding cells, and there also appear to be more mito- chondria. Eakin and Kuda (1971), who report that occasional tubules of the bulbs open into the ventricular lumen, provide further ultrastructural descriptions of these unusual cells. A number of investigators (Dilly, 1969b; Eakin and Kuda, 1971; Olsson, 1975) have pointed out the remarkable structural similarities between the tubulated bulb cells of the tunicate CNS and the coronet cells of the teleost CNS. (See Jansen and Flight [1969], Harrach [1970], Galer and Billenstein [1972], and Rossi and Palombi [1976], for descriptions of the coronet cells.). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appea
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
