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A total of 17 species, in 14 genera of majids have been examined for sperm ultrastructure. The present account describes the sperm of six of these species, in two subfamilies: Pisinae—Sphenocarcinus orbicutalus and Sphenocarcinus stuckiae and Inachinae—Cvnonmia furici, Grypacheus hyalinure. Platymaia rebierei and Macropodia longirostris. M. longirostris has the only eubrachyuran sperm in which the acrosome is known to depart radically from a subspheroidal form. The acrosome is semilunar in shape and is bordered by a very thin layer of cytoplasm and an unusually uniform, narrow band of chromatin. The apical surface of the acrosome is almost flat, though slightly concave, whereas the posterior surface forms a hemisphere, and is almost completely occupied by the thin. centrally perforate, electron dense operculum. The bulk of the acrosome consists of a homogeneous. moderately electron dense outer acrosome zone. This surrounds a small inner acrosome zone internal to which is an ellipsoidal, pale perforatorium capped by a central acrosome zone. Majid sperm arc distinguished by a flattened and/or centrally depressed operculum; a further characteristic is that the pointed perforatorium is relatively short and frequently does not reach the operculum. They vary inter aim with regard to presence or absence of a posterior median process and, apparently. of centrioles and of microtubules in the nuclear arms and in the number of these arms. Perforation of the operculum, seen in the Pisinae, is not constant in the Inachinae. Spermatozoal ultrastructure offers no certain support for a close relationship of majids with parthenopids or hymenosomatids. [ABSTRACT FROM AUTHOR]

The article discusses the biodiversity threats on the island of New Caledonia as the result of mining and other development. The authors describe the geologic history of the island and the endemic species which resulted. They argue that the entire list of endemic flora and fauna should be on the endangered species list due to their limited geographic extent. They urge that a scientific expedition be conducted to catalogue the wildlife. They suggest that development decisions should not be made without first knowing the extent of the biodiversity value.

We present detailed records of trace metals and carbon isotopes to understand siliceous spicule formation in the deep-sea lithistid sponge Corallistes undulatus Levi and Levi, 1983 (Demospongiae: Corallistidae). X-ray analysis of two longitudinal sections removed from the lamellae of the cup-shaped sponge revealed 144 and 137 light and dark density band-pairs, respectively, within the siliceous skeleton. Four portions of silica were removed along one of the sections for silicon-32 (32Si) dating in order to constrain the overall extension rate of the sponge. Although there was some variability in the 32Si data, the overall age established using these data indicated that the sponge was between 135 and 160 yr old. This agreed well with the counts of density band-pairs, indicating that these band-pairs represent an annual deposition of layers of silica in the desma skeleton. Links between silica deposition and growth (food supply) were established using the Δ14carbon (C) and δ13C signatures of organic material trapped with the spicule matrix and the zinc content of the silica. A carbon budget based on these results indicated that the amount of fresh, labile surface export organic carbon reaching C. undulatus was not sufficient to support its growth. The Δ14C results for organic carbon trapped in the silica desmas, deposited after the 1960s, supports this assertion; only a small atmospheric nuclear weapons 'bomb' spike was observed in the Δ14C data. Taken together, the Δ14C, δ13C, and trace-metal results all indicate that the organic carbon source to C. undulatus is likely to be a mixture of fresh, labile, surface-derived material and older, perhaps sediment-derived material, with the latter being dominant. [ABSTRACT FROM AUTHOR]