. D Fig. 5. A. Cells of the digestive sac in surface view. B. Same in section showing striated border. C. Section of the plated side walls of the stomach showing the grooves in the chitin as it is laid down over each cell and the closeness of the opposite walls of the gut: ch. chitin; gr. intercellular groove in the chitin; /. lumen of the gut; n. nucleus. D. Surface view of the chitin. MUSCULATURE The musculature of the fore-gut of Nebaliopsis is shown in Fig. 6 C. The similarities to the other Nebaliacea are striking. The oesophagus and stomach are sheathed in strong bands of circular muscle
. D Fig. 5. A. Cells of the digestive sac in surface view. B. Same in section showing striated border. C. Section of the plated side walls of the stomach showing the grooves in the chitin as it is laid down over each cell and the closeness of the opposite walls of the gut: ch. chitin; gr. intercellular groove in the chitin; /. lumen of the gut; n. nucleus. D. Surface view of the chitin. MUSCULATURE The musculature of the fore-gut of Nebaliopsis is shown in Fig. 6 C. The similarities to the other Nebaliacea are striking. The oesophagus and stomach are sheathed in strong bands of circular muscles [ and ). These bands are many times thicker than the corresponding ones in Nebalia, while the tissue between them and the chitin is comparatively much reduced. They cease abruptly at the end of the fore-gut. Acting antagonistically to these circular muscles are the dilator muscles. The dorsal dilators () are probably homologous with the anterior dorsal dilators [) of Nebalia, as the groove muscles which lie close to the dorsal ridge between the anterior horns of the stomach run between them and
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Keywords: ., bookcentury1900, booksubjectocean, booksubjectscientificexpediti
