BACKGROUND AND AIMS Nickel (Ni) hyperaccumulation is a rare form of physiological specialization shared by a small number of angiosperms growing on ultramafic soils. The evolutionary patterns of this feature among European members of tribe Alysseae (Brassicaceae) are investigated using a phylogenetic approach to assess relationships among Ni hyperaccumulators at the genus, species and below-spe...

Blue mussels of the genus Mytilus have an unusual mode of mitochondrial DNA (mtDNA) transmission: males receive mtDNA from both parents and transmit their paternal mtDNA to their sons; females receive mtDNA only from their mother (Skibinski, Gallagher, and Beynon 1994~2, 1994b; Zouros et al. 1994~2, 1994b). This mode of mtDNA transmission has been termed “doubly uniparental inheritance” (DUI; Z...

341 CLARK, A. W. The fine structure of the eye of the leech, Ilelobdella stagnalis 349 EAKIN, R. M., WESTFALL, JANE A. and DENNIS, M. J. Fine structure of the eye of a nudibranch mollusc, Hermissenda crassicornis 359 CHAPMAN, J. A., ELVES, M. W. and GOUGII, J. An electron-microscope study of the in vitro transformation of human leucocytes I. Transformation of lymphocytes to blastoid cells in th...

Concentrations of 13 radionuclides (137Cs, 129I, 60Co, 152Eu, 90Sr, 99Tc, 241Am, 238Pu, 239,249Pu, 234U, 235U, 236U, 238U) were examined in seven species of invertebrates from Amchitka and Kiska Islands, in the Aleutian Chain of Alaska, using gamma spectroscopy, inductively coupled plasma mass spectroscopy, and alpha spectroscopy. Amchitka Island was the site of three underground nuclear test (...

In recent years, a variety of animals have been found which are able to synthesize the ferromagnetic mineral magnetite (Fe 3 O 4). Lowenstam (1962) originally recognized biogenic magnetite in the radular teeth of a primitive marine mollusc, the chiton (Polyplacophora), and since then it has been identified as a precipitate in several magnetically sensitive organisms, including honey bees also r...

35 36 The rock type of hard-substrata marine habitats can affect numerous benthic invertebrates, but 37 little is known of the effects on molluscan assemblages, for example, the chitons often found 38 under intertidal boulders. We compared chiton assemblage composition, abundance, species 39 richness, and patterns of frequency distribution in ten boulder-fields containing either hard 40 metamor...

Polyplacophorans, or chitons, are an important group of molluscs, which are argued to have retained many plesiomorphic features of the molluscan body plan. Polyplacophoran trochophore larvae posses several features that are distinctly different from those of their sister trochozoan taxa, including modifications of the ciliated prototrochal cells, the postrochal position of the larval eyes or oc...