. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 346 ALDEN P. STICKNEY nective tissue in this region. A larger branch from each of these nerve trunks follows the gonoduct from the genital vesicle deep into the gonad itself. The wall of the visceral mass contains abundant muscular tissue; connecting these walls transversely are numerous bands of muscle fibers which pass through the gonad. The histological structure of the gonad alveoli has been described by Coe and Turner (1938). These alveoli consist of a thin basement membrane or wall surrounding a group of large, transpa
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 346 ALDEN P. STICKNEY nective tissue in this region. A larger branch from each of these nerve trunks follows the gonoduct from the genital vesicle deep into the gonad itself. The wall of the visceral mass contains abundant muscular tissue; connecting these walls transversely are numerous bands of muscle fibers which pass through the gonad. The histological structure of the gonad alveoli has been described by Coe and Turner (1938). These alveoli consist of a thin basement membrane or wall surrounding a group of large, transparent follicle cells, which may fill the alveolus solidly, or may separate in the center to form a lumen. The gametes arise from the basement membrane between the peripheral follicle cells. The gonoducts and their branches resemble the alveoli in histological structure, except that the large, transparent cells tend to be more elongate, oriented perpendicularly to the base- ment membrane, and a lumen is always present. Gametes are also proliferated from the basement membrane of the gonoducts, although less abundantly than in the alveoli. In some specimens the transparent cells lining the gonoduct are reduced in size and appear to be disintegrating. Where this process is taking place, clusters of clear droplets appear in the lumen, suggesting holocrine secretory FIGURE 2. Cross-section through the visceral mass of Myn arcnarla at the level of the genital papillae. Papillae (P), cerebro-visceral nerve commissures (N), transverse muscles (M) and dorsal pallial chamber (E) are indicated. X 35. FIGURE 3. Cross-section through the visceral mass of M'ya arcnarla at the level of the genital vesicle (V). X 35. FIGURE 4. Cross-section of terminal gonoduct of Mya arcnarla taken through genital papilla, showing both ciliated columnar (C) and non-ciliated "secretory" cells (S). X 300. FIGURE 5. Longitudinal section through genital papilla of Spisitla solidissima, showing
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
