. Elements of geology. Geology. 46 LYELL'S ELEMENTS OF GE0L0G7 Distinction of Freshwater from Marine Formations. Fiff. Fin-. 43. to distinguish the two by good generic characters. But, as a general rule, the fluviatile species are small- er, smoother, and more globular than the marine; and they have never, like the Neritee, the inner mar- gin of the outer lip toothed or crenulated. (See Fig. 41.) A few genera, among which Cerithium (Fig. 42.) is the most abundant, are common both to rivers and the sea, having species peculiar to each. Other genera, like Auricula (Fig. 36.), are amphibious
. Elements of geology. Geology. 46 LYELL'S ELEMENTS OF GE0L0G7 Distinction of Freshwater from Marine Formations. Fiff. Fin-. 43. to distinguish the two by good generic characters. But, as a general rule, the fluviatile species are small- er, smoother, and more globular than the marine; and they have never, like the Neritee, the inner mar- gin of the outer lip toothed or crenulated. (See Fig. 41.) A few genera, among which Cerithium (Fig. 42.) is the most abundant, are common both to rivers and the sea, having species peculiar to each. Other genera, like Auricula (Fig. 36.), are amphibious, liv- ing both in freshwater and on land. The terrestrial shells are all univalves. The most abundant genera among these, both in a recent and fossil state, are Helix (Fig. ), Cyclostoma, Pupa, (Fig. 44.), Clausilia, Bulimus (Fig. 43.), and Acha- tina ; which two last are nearly allied and pass into each other. The same may be said with almost equal truth of Pupa and Clausilia. Fia-. 44. Fiff. 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 Lyell, Charles, Sir, 1797-1875; Gibbes, Lewis Reeve, 1810-1894, former owner. DSI; Merrill, George P. (George Perkins), 1854-1929, former owner. DSI. Philadelphia : James Kay, Jun. and Brother ; Pittsburgh : C. H. Kay & Co.
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Keywords: ., bookauthorlyellcharlessir17, bookcentury1800, booksubjectgeology
