Bryozoan frontal shields: studies on umbonulomorphs and impacts on classification

Umbonuloid frontal shields arc described in the type species of Lepraliella, Drepanophora, Frurionella, Tessaradoma, Hincksipora, Stephanopora , and Pseudolepralia. Consequences to classification include the following: the family group names Lepralielloidea and Lepralicllidae have subjective priority over Umbonuloidea and Celleporariidae, respectively; Cylindroporeh is excluded from the Tessaradomidae and included in the Gigantoporidae; Tessarudoma bifax Cheetham is included in Srnithsonius (Bifaxariidae); Hincksiporidae is confirmed as a family of Lepralielloidea; Stephanoporu , with newly discovered dimorphic orifices, comprises two species which are the basis for a new exechonellid subfamily Stephanoporinae; and a new umbonulomorph superfamily, Pseudolepralioidea, is established for Pseudolepraliu (Pseudolepraliidae). Kladapheles gen.n., is established for an erect branching species of Lepraliellidae from New Zealand.     

Regional growth patterns in the hypocotyls of etiolated and green cress seedlings in light and darkness

Abstract. A system is described whereby seedling development can be analysed in terms of growth rates of specific 1 mm regions of the hypocotyl. The technique involves time-lapse photography of marked hypocotyls in a specially designed chamber which accommodates seedlings in various orientations with respect to gravity, and under irradiation regimes differing in light quality, quantity and direction. The results of a preliminary study of the upward growth of etiolated or green cress seedlings in darkness or overhead while light are reported. Highest growth rates in etiolated seedlings were observed in zones in the upper one-third of ihe hypocotyl. In green seedlings, growth was more prominent within the subapical zones. Light further restricted growth of the median and basal zones in both types of seedling. However, in their immediate responses to the onset of irradiation, green and etiolated seedlings differed markedly. In etiolated seedlings, recovery of growth at the apex was accompanied by the development of inhibition in the median-basal regions; green seedlings showed a transient inhibition of growth in the apical zone together with a strong immediate inhibition in the median-basal regions.     

Macromolecules in brachiopod shells: characterization and diagenesis

An immunological investigation was conducted of soluble intra-crystalline macromolecules isolated from living and fossil brachiopod shells, which had previously been used for an immunologically based study of phylogeny (serotaxonomy). The soluble intra-crystalline macromolecules comprised 0.03% by weight of the extant shell material. Bulk analysis and gel electrophoresis indicated that the organic material is predominantly glycoprotein, and contains up to 30% by weight carbohydrate. Treatment of the macromolecules with periodate and proteinase K revealed that antibodies were raised predominantly against the carbohydrate moieties. Using a specially adapted dot blot immunobinding assay (DIBA) the decay in immunological signal over geological time was determined. Pleistocene shells have lost between 99 and 99.9% of immunological reactivity, and original antigenic determinants form a declining proportion of total organic matter. It is suggested that condensation reactions between amino acids and sugars account for the rapid destruction of determinants; this has important implications for the direction of future studies on fossil macromolecules. □ Serotaxonomy, biomolecular palaeontology, glycoproteins, melanoidins, brachiopods.     

Structure and Function of the Adrenal Gland of Fishes

The structure and distribution of the adrenal gland in fishesis reviewed. Studies on the in vitro and in vivo biosynthesisof adrenocortical steroids and their occurrence in the bloodof fishes are evaluated in the light of modern techniques forthe identification and quantification of steroids. There followsan appraisal of some literature dealing with the adrenocorticalcontrol of intermediary metabolism and ion transport in fishes.