. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. 8 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY young specimens (Fig. 2). This feature remains constant during development except in some old specimens in which the edge Figure 2. Line drawing of n specimen mm. to show various structures of the shell in cross-section. The form of the shell changes with growth. The prodissoconch is broadly rounded, slightly longer than high. The scallop con- tinues to be slightly compressed dorso-ventrally until it reaches a size of 1 to mm. at which time the height and
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. 8 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY young specimens (Fig. 2). This feature remains constant during development except in some old specimens in which the edge Figure 2. Line drawing of n specimen mm. to show various structures of the shell in cross-section. The form of the shell changes with growth. The prodissoconch is broadly rounded, slightly longer than high. The scallop con- tinues to be slightly compressed dorso-ventrally until it reaches a size of 1 to mm. at which time the height and length are about equal. The shell now gradually becomes more and more compressed laterally so that it is at its greatest extent in specimens between 70 and 90 mm. in height. Then the shell slowly begins to broaden again, and specimens 110 to 120 mm. assume a broadly rounded shape of similar height and length. The broadening of the shell continues and, in an average series, specimens larger than 120 mm. become increasingly longer than high. Individual specimens sometimes vary considerably but the measurements in Table 1 typify the general average of the sea scallop. Table 1 - - Ratios of height to length illustrating the changes in shell symmetry during growth Height (mm.) Length (mm.) Ratio Height (mm.) Length (mm.) Ratio * X X ** X X X X X X X X X X X *** X *Str;tight-hinge veliger * "Completed dissoconch •••Largest scallop recorded in the literature (See Norton 1931). 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 not perfectly resemble the original Harvard University. Museum of Comparative Zoology. Cambridge, Mass.
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