. Bulletin - New York State Museum. Science. â Strophonella (Amphistrophia) continens shell a series of fine threadlike lines separated by flat spaces in* which lie fascicles of lesser order, sometimes but a single series consisting of six or more lines, sometimes three or more subordinate series. The general expression of the surface ornament however is that of fine sharply fasciculate striation. On the interior of the valves the surface is highly pustulose throughout except on the muscle areas, the pustules being arranged in radial rows. These are the usual characters of the adult shell. The
. Bulletin - New York State Museum. Science. â Strophonella (Amphistrophia) continens shell a series of fine threadlike lines separated by flat spaces in* which lie fascicles of lesser order, sometimes but a single series consisting of six or more lines, sometimes three or more subordinate series. The general expression of the surface ornament however is that of fine sharply fasciculate striation. On the interior of the valves the surface is highly pustulose throughout except on the muscle areas, the pustules being arranged in radial rows. These are the usual characters of the adult shell. The young of the species are readily recognized as normally convex shells with sharp and strong plications and this is a condition which when maintained to maturity is expressed in such species as S t r o p h e o- donta arata of the Schoharie grit of New York. Variant i equiplicata. We find a few of these forms in which the simple sharp plication of growth is not broken up into- fascicles but continues sharp over the body of the shell with very sparse intercalations, so that the surface conveys the expression of subequal plication and not of fasciculation. Such forms are at once distinguished by their exterior. The initial striae are ai. 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 New York State Museum; New York State Museum. Albany : New York State Education Dept
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectscience, bookyear1887
