. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SHELL SWALLOWING IN BORING SNAILS 333 30 0> 0 E a H— o b 20 10. 0 20 15 Thickness of lamellae (microns) FIGURE 15. Plot of thickness of lamellae in fractured shell of adult Mvtilits ctlnlis. Schaadt, and Peters, 1974) creates spaces among them, thereby weakening the shell sufficiently for the nulnla to dislodge and remove the units. A similar type of dissolution of the shell of Mytilus ediilis is caused by secretions from the shell burrowing polychaete, Polydora wchstcri (Zottoli and Carriker, 1974). If prisms occ
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SHELL SWALLOWING IN BORING SNAILS 333 30 0> 0 E a H— o b 20 10. 0 20 15 Thickness of lamellae (microns) FIGURE 15. Plot of thickness of lamellae in fractured shell of adult Mvtilits ctlnlis. Schaadt, and Peters, 1974) creates spaces among them, thereby weakening the shell sufficiently for the nulnla to dislodge and remove the units. A similar type of dissolution of the shell of Mytilus ediilis is caused by secretions from the shell burrowing polychaete, Polydora wchstcri (Zottoli and Carriker, 1974). If prisms occur parrallel to the surface of the borehole ('much as in Fig. 5rl, Zottoli and Carriker, 1974), the radula breaks out long fragments of shell (Fig. 1, this paper) ; on the other hand, if prisms occur more or less at right angles to the surface of the borehole (much as in Fig. 13, Carriker, Schaadt, and Peters, 1974), the radula tends to cut out mostly short pieces of shell units (Fig. 5, this paper). The mucoid material which blankets shell fragments on their journey from the buccal cavity to the stomach and out the intestine probably insulates them against further corrosion from acid juices in the stomach. More importantly, however, the mucoid envelope must also serve to insulate sharp edges of shell fragments which might otherwise lacerate the delicate ciliated epithelium of the alimentary canal. Since the mucoid material undoubtedly also contains a large proportion of viscid secretion from the accessory boring organ, it would appear that a secondary function of the secretion from this gland is to contribute to clothing of sharp shell fragments on their way down the digestive tract. It is inviting to speculate whether hole boring contributes calcium carbonate to the calcium anabolism of boring snails. Observations reported in this paper, how- ever, suggest that very little dissolution of the shell occurs in the stomach. The question could be settled by incorporating a calci
Size: 1720px × 1453px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
