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Lissarca notorcadensis, a small pallial-brooding mollusc with a circum-Antarctic distribution, is frequently found attached by stout byssal threads to the spines of sea urchins. Here, complete ontogenetic series can be found. Using standard, structural definitions, the prodissoconch I of L. notorcadensis is small compared to the large prodissoconch II, a feature atypical of brooded young and possibly reflective of a planktotrophic past. Fine commarginal striae are found on prodissoconch II of this subtidal clam, which also possesses more pronounced commarginal striae on the dissoconch prior to brood release. The provinculum is retained and remains functional well into adulthood. A small central ligament pit is present through the postlarval stages. This develops into a large, triangular pit in adulthood that shows obvious growth lines. Calcareous, presumably aragonitic fibres develop in the ligament of specimens still retained in the adult brood. Five to six adult hinge teeth are formed on either side of the ligament. Alignment of shell valves by these well-developed teeth is augmented by retention of larval denticles. The functional and structural demise of the provinculum occurs between 4 and 7 mm shell height and results from denticle erosion and subumbonal shell overgrowth. Many canals permeate larval and adult valves, but external pores in the adult shell differ from those of the larval shell and could indicate mode of formation. Prodissoconch form, provinculum retention, and shell canals are considered primitive traits.

We report the results of a study with proton-induced X-ray emissions (PIXE) of the distribution and concentration of 15 chemical elements (Na to Sr in periodic chart) in four microstructural and two mineralogical regions of shell of rapidly growing adult oysters [Crassostrea virginica (Gmelin)]. Hatchery-raised oysters were grown in Broadkill Estuary, Delaware, USA, for 16 wk in summer 1978. Their valve edges were filed as a marker, and the oysters were replaced in the estuary, where they grew rapidly. Shell deposited after marking had a normal microstructure and mineralogy after a narrow zone of disturbance. After 17 d oysters were sacrificed, and different mineralogical and microstructural regions of valves of three oysters, and parts of valves of two oysters, were analyzed for the elements Na to Sr. Quadrats (2.5 × 0.45 mm) included three calcitic groups (prismatic, foliated, chalky) and one aragonitic (myostracal) microstructural group; four quadrats were on the exterior and five on the interior of right and left valves. Inhalant and exhalant margins of valves and ground right and left valves of one oyster were also analyzed. Elemental chemistry of different regions of shell varied among the three microstructural groups within the single calcitic polymorph, between aragonitic and calcitic regions, and between exhalant and inhalant margins of the valves. Elements were most concentrated in the prismatic region of the right valve. Element concentrations were similar in ground right and left valves, except for higher levels of Si, Fe, and Zn in the right valve (corresponding to their high contents in prismatic shell) and of Cl in the left valve (reflecting high concentration in chalky shell, abundant in this valve). Na, Mg, Cl, Cr, Cu, Zn and Br were more concentrated in prismatic than in foliated shell. Chalky shell contained higher concentrations of Na than did prismatic shell, and high concentrations (but lower than in prismatic shell) of Mg, Cl, Ti, Mn, Fe, Zn and Br. Element concentration in myostracum was approximately the same as, or lower than, in foliated shell, except for Sr, which was higher than that in any other shell group. In the right valve most elements were concentrated in inhalant margins, and on the left valve, in exhalant margins. With increased weathering of the exterior surface of prismatic shell, Mg, Si, and Mn increased in concentration and Na, Al, Cl, Ti, Cr, Fe, Br, and Sr decreased.

A freshwater bioprobe, combining the Asiatic Clam, Corbicula fluminea (Müller) and the laser microprobe mass spectrometer (LAMMA), can determine anthropogenic chemical contamination of freshwater systems. Laser generated mass spectra from the periostracal layers of clams contaminated with either a salt, potassium bromide, or an aromatic compound, phenol, produce distinctive mass spectral signatures that are different from uncontaminated clams. Uncontaminated clams have characteristic signatures with distinctive spectral peaks less than m/z 41; while exposed clams have many strong peaks well above this m/z. This freshwater bioprobe, using LAMMA to analyze the surface of clams, can be used as a screening tool for monitoring the water-treatment systems, for determining the source of contaminated baseflow and return flow discharge to streams, and for monitoring the water chemistry of a body of water. This system exploits the facility of using the shell instead of soft tissue with the LAMMA and has potential to detect anthropogenically-derived chemical stress.

Aqueous-phased xenobiotic contaminant exposure can biochemically modify newly generated periostracum of the Asian freshwater bivalve,Corbicula fluminea. Laser-induced desorption of partially polymerized periostracum produces spectra distinguishable from mass spectral images generated from uncontaminated periostracum. Organic xenobiotic contamination putatively impedes full polymerization of the periostracin protein. The detection of the effects of pollution on periostracum by the laser microprobe mass analyzer constitutes a novel bioprobe for the definitive but qualified detection of xenobiotic contamination.

The freshwater limpet, Ferrisla rivularis, was found in several watersheds in south-central and south-western Pennsylvania. Shell size was not significantly correlated with stream pH, calcium, iron, or manganese concentrations. Limpets tolerated stream iron concentrations up to 0.36 mg/l and manganese concentrations up to 0.25 mg/l. The shells of these snails were quickly and heavily colonized by adherent or embedded diatoms, and shell size was significantly positively correlated with diatom coverage (P=0.050). Diatom coverage was significantly positively correlated with stream phosphate concentration (P=0.002).

The heats of reaction of CuO-Cu(OH)2-H2O samples with aqueous HClO4 have been obtained as a function of concentration. Extrapolated to the normal standard state, the values are ΔH°298 = -15.00 and -15.37 kcal. per mole for CuO and Cu(OH)2, respectively. These data are consistent with thermochemical paths based on data in the literature. The entropy of Cu2+(aq) has been determined as -21.5 ± 1.5 cal. per mole 0 K. No evidence was obtained for stable “hydrates” of CuO in the H2O/CuO range 0 to 1.25. © 1969, American Chemical Society. All rights reserved.

1. The effects of temperature acclimation on electrical properties of earthworm axons (Lumbricus terrestris) were studied using intracellular stimulating and recording techniques. 2. Cold acclimation, compared to warm acclimation, was associated with decreased action potential duration and cable input resistance and increased maximum rate of rise and decline of the action potential and increased excitation threshold. In each case the direction of change occurring during acclimation to 5° C was opposite to that occurring immediately after cooling to 5° C, i.e., the acclimation changes were compensatory. 3. The significance of these changes is discussed with regard to their influence on over-all nerve function after thermal acclimation. © 1969 Springer-Verlag.

The reaction of 2,2′-bipyridylamine (abbreviated BPAH) with divalent nickel salts results in the formation of several products, the type of which depends on the metal:ligand ratio and the coordinating ability of the associated anion. Thus, tetrahedral [Ni(BPAH)Cl2] and octahedral [Ni(BPAH)3] (ClO4)2 and [Ni(BPAH)2Cl2] have been isolated and characterized. In these complexes, dipyridylamine coordinates in a bidentate manner through the two pyridine nitrogens. Deprotonation of the amine at ambient temperature in butanol results in the conversion of the paramagnetic [Ni(BPAH)2Cl2] species into a six-coordinate polymeric material of the general formula Ni(BPA)2 where the deprotonated bipyridylamine moiety (ab¬breviated BPA) is coordinating in a tridentate manner with the amine nitrogen acting as a bridge. This polymer is cleaved quite readily by the action of water, pyridine, and, presumably, other complexing solvents. Deprotonation of [Ni(BPAH)-Cl2] at high temperatures in naphthalene or reaction of the deprotonated polymer with nickel(II) chloride, also at high temperatures, yields a red crystalline trinuclear complex of the molecular formula [Ni3(BPA)4Cl2]. Deprotonation of bis(2,2′-bipyridylamine)copper(II) chloride and bis(2,2′-bipyridylamine)palladium(II) perchlorate give the expected four-coordinate square-planar product. The deprotonated complexes of palladium, copper, and nickel are compared and corre¬lations are made between their ease of formation and the geometry and electronic arrangement of the central metal ion. © 1968, American Chemical Society. All rights reserved.