. Elements of zoology, or, Natural history of animals / ed. by Reese. Zoology. Adult Shell. Pteroceras Scorpio. 790. The operculum is principally confined to the aquatic Gasteropoda. It is sometimes of the same texture as the shell itself, and sometimes horny. It does not always close the en- tire mouth of the shell, but it is sometimes made to fit it, at all stages of growth, with the most beautiful accuracy. Some of the land species also possess an operculum; but in general they are destitute of it, and they form during hybernation a temporary closure to the mouth of the shell, by a vis
. Elements of zoology, or, Natural history of animals / ed. by Reese. Zoology. Adult Shell. Pteroceras Scorpio. 790. The operculum is principally confined to the aquatic Gasteropoda. It is sometimes of the same texture as the shell itself, and sometimes horny. It does not always close the en- tire mouth of the shell, but it is sometimes made to fit it, at all stages of growth, with the most beautiful accuracy. Some of the land species also possess an operculum; but in general they are destitute of it, and they form during hybernation a temporary closure to the mouth of the shell, by a viscid secre- tion, which hardens into a thin plate, and includes within it a bubble of air. Behind this, a second, and a third, similar partition is occasionally found, as in the common snail. 791. The subdivision of this extensive class into orders, may be best aifected by arranging the different tribes according to 81G. What other changes a> 817. VVhui other spears ifl. 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 Reese, David Meredith, 1800-1861. New York : A. S. Barnes
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Keywords: ., bookcentury1800, bookdecade1840, bookpublishe, booksubjectzoology
