. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. mm B. mm FIGURE 1. Eggs of Mcltiinpits bidcntatits: (A) part of an egg-strand from a newly laid egg-mass, showing the two tubular gelatinous layers surrounding the eggs; and (B) an egg after 11-12 days of development containing a well-differentiated and active veliger larva. M clam pus with the detailed nomenclature set up for the higher limnic pulmonates hy Bondesen (1950), but it is worth noting that no pedal glands are involved in this egg-mass secretion. Among the higher limnic Basommatophora, "external"
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. mm B. mm FIGURE 1. Eggs of Mcltiinpits bidcntatits: (A) part of an egg-strand from a newly laid egg-mass, showing the two tubular gelatinous layers surrounding the eggs; and (B) an egg after 11-12 days of development containing a well-differentiated and active veliger larva. M clam pus with the detailed nomenclature set up for the higher limnic pulmonates hy Bondesen (1950), but it is worth noting that no pedal glands are involved in this egg-mass secretion. Among the higher limnic Basommatophora, "external" secretions from the foot are important as the origin of the tough outermost coatings of the egg-capsules in such forms as ancylid limpets (Russell-Hunter, unpublished). The tubular string membrane in Mclatnpiis appears to form the general jelly matrix of the egg-masses as they "age" during the first days after laying, and is usually indistinguishable by the time of hatching. The spherical envelope, although con- tinuous in the egg-strand, is concentrated primarily around the egg-shells them- selves, appearing as optically distinct fine concentric bands in life, with lesser amounts in each "neck" between eggs. \Yithin this, and connecting each egg with the preceding egg is a fine string-like structure, termed the allochalazal strand, which is probably continuous with the outer portion of the egg-shell. Attached at the points of indentation in the ends of the egg-shell (Figs. LA and B), the allochalazal strand has been found to be mechanically important in the process of hatching which is described in the following section. The organic content of the egg-mass layers (excluding the eggs themselves) is relatively low and it is obvious that free water is taken up at oviposition. Egg-. 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 n
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
