. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 444 FRANCIS J. BERNARD AND CHARLES E. LANE parts and anal flaps substantiate the observation that absorbed copper moves away from the absorbing surface until some obstacle hinders its further movement. B. Attached cyprids As was described for planktonic barnacle cyprids, little increase was observed in either size or number of copper-containing vacuoles in parenchymatous connec- tive tissue as the medium was enriched in copper ion. A trace of copper pre- cipitate was found near the anterior pigment mass in some specimens whe
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 444 FRANCIS J. BERNARD AND CHARLES E. LANE parts and anal flaps substantiate the observation that absorbed copper moves away from the absorbing surface until some obstacle hinders its further movement. B. Attached cyprids As was described for planktonic barnacle cyprids, little increase was observed in either size or number of copper-containing vacuoles in parenchymatous connec- tive tissue as the medium was enriched in copper ion. A trace of copper pre- cipitate was found near the anterior pigment mass in some specimens where none was observed in animals of the same stage from normal sea water. The addition of copper ion to the medium was accompanied by a marked increase in the number and density of deposits in the hind-gut epithelium similar to that described for planktonic cyprids. Stomach secretion of copper, while increased over that a. FIGURE 6. Loci of copper accumulation in attached cyprids exposed to excess ambient copper and stained with technique, (a) In the connective tissue underlying the cyprid carapace, (b) Within the food mass and in the secretory region of the stomach epithelium, (c) In the thoracic epidermal cells and in the secretory portion of the hind-gut. shown by animals from this stage in normal sea water, was somewhat less than had been observed in the previous stage (Fig. 6). If the rate of absorption of copper were proportional to its concentration within thoracic epidermal cells, then clearly less copper was taken up by cyprids after attachment than before. It is suggested that this reduced absorption results from decreased exposure of thoracic surfaces to sea water because the cirri are in- active during this stage and the mantle circulation is correspondingly reduced. Sites of heavy copper concentration in the planktonic cyprid, such as the ventro- lateral surfaces of the anterior part of the thorax, show somewhat less copper deposition in attached barnacles. T
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