Shell-fish industries . r transported to them by the gills. Underfavorable conditions, diatoms are collected a few at atime, and are sent across the palp ridges to the muddy water the particles increase in number untilthe palps respond by diverting everything received tothe outgoing tracts. This may be proved experimentally, though theoperator must exercise care and skill. Very fine grainsof carmine, dropped on gills or palps of any bivalve, invery small quantities, may be observed, with the aid of aglass, to pass into the mouth. This simulates conditionsfavorable for feeding, when di
Shell-fish industries . r transported to them by the gills. Underfavorable conditions, diatoms are collected a few at atime, and are sent across the palp ridges to the muddy water the particles increase in number untilthe palps respond by diverting everything received tothe outgoing tracts. This may be proved experimentally, though theoperator must exercise care and skill. Very fine grainsof carmine, dropped on gills or palps of any bivalve, invery small quantities, may be observed, with the aid of aglass, to pass into the mouth. This simulates conditionsfavorable for feeding, when diatoms are steadilystrained, a few at a time, from clear water. When 62 Our Food Mollusks larger quantities of carmine grains are used, their nun-ber finally causes the palps to reject them, the ciliatcmargins often being folded over so as to sweep the striated surfaces of the palps, if carmine ha;-fallen directly on them, and they are able to clean themselves in still another way that cannot be described Fig. 15.—Cilia currents on mantle (m) and palp (/>) of theoyster (Ostrea virginica). The general direction of currents and the possibleroutes for food or mud in the mantle chamber of theoyster will be understood without description by a studyof Figures 3 and 15. The gills are represented as hav-ing been removed in the latter figure, their former lineof attachment to the mantle being shown by the line will be seen that undesirable matter is cast out of thebody over the edges of the mantle between the points Aand B, and that this is the most favorable region for sucha discharge. If farther back, as below C, this would Ciliary Mechanisms 63 have to be accomplished (hrectly against the incurrentstream of water. The palps function, as in Venus, indisposing of material that they receive from the gills. There is a widespread belief that oysters and clamsmay be fattened with such substances as those well acquainted with the subject often havesu
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyo, bookyear1910
