New Species of Lissodendoryx Topsent, 1892 (Demospongiae, Poecilosclerida, Coelosphaeridae) and Myxilla Schmidt, 1862 (Demospongiae, Poecilosclerida, Myxillidae) from the Northeast Pacific.

Collections of sponges by the late Dr. William C. Austin and the authors (N. McDaniel, R. Harbo and B. Ott) provided material for descriptions of new species from two genera of Poecilosclerida for shallow waters of Southern British Columbia, Canada and Northern Washington, USA: Lissodendoryx and Myxilla. There have been no new species of these two genera described for the Northeast Pacific since Laubenfels' work in central California (Laubenfels 1930, 1932) and Lambe's reports in 1893 to 1895 for Geological Survey of Canada sponge collections from British Columbia, Canada to the Bering Sea. We describe three new species of Lissodendoryx (Lissodendoryx) (Demospongiae, Poecilosclerida, Coelosphaeridae) and one new species of Myxilla (Myxilla) (Demospongiae, Poecilosclerida, Myxillidae): L. (L.) barkleyensis n. sp., L. (L.) littoralis n. sp., L. (L.) toxaraphida n. sp. and M. (M.) austini n. sp. Lissodendoryx (L.) barkleyensis n. sp. is cave-dwelling, has acanthostyles 112-260 µm, tornotes 107-177 µm, arcuate isochelas 8-28 µm and two sizes of sigmas 18-29, 26-55 µm. Lissodendoryx (L.) littoralis n. sp. fistulate habitus is adapted to muddy substrates similar to some Polymastia species also found commonly in the Northeast Pacific. It has subtylostyles 185-336 µm, tylotes 112-229 µm, arcuate isochelas 11-23 µm, and sigmas 30-75 µm. Lissodendoryx (L.) toxaraphida n. sp. is the only described Lissodendoryx species with raphides shaped like toxas. It has acanthostyles 140-286 µm, tornotes 143-195µm, arcuate isochelas 18-34 µm and toxiform raphides 65-156 µm. Myxilla (M.) austini n. sp. has a fistulate habitus and both tornote and tylote megascleres. It appears to be tolerant of low oxygen environments. Myxilla (M.) austini n. sp. has smooth to sparsely spined styles 193-353 µm, tylotes 153-221 µm, tornotes 174-260 µm, two sizes of anchorate isochelas 13-27, 42-81 µm, and two sizes of sigmas 13-47, 33-78 µm. All specimens were collected from shallow water (intertidal to 25 m).

The biology of glass sponges.

As the most ancient extant metazoans, glass sponges (Hexactinellida) have attracted recent attention in the areas of molecular evolution and the evolution of conduction systems but they are also interesting because of their unique histology: the greater part of their soft tissue consists of a single, multinucleate syncytium that ramifies throughout the sponge. This trabecular syncytium serves both for transport and as a pathway for propagation of action potentials that trigger flagellar arrests in the flagellated chambers. The present chapter is the first comprehensive modern account of this group and covers work going back to the earliest work dealing with taxonomy, gross morphology and histology as well as dealing with more recent studies. The structure of cellular and syncytial tissues and the formation of specialised intercellular junctions are described. Experimental work on reaggregation of dissociated tissues is also covered, a process during which histocompatibility, fusion and syncytialisation have been investigated, and where the role of the cytoskeleton in tissue architecture and transport processes has been studied in depth. The siliceous skeleton is given special attention, with an account of discrete spicules and fused silica networks, their diversity and distribution, their importance as taxonomic features and the process of silication. Studies on particle capture, transport of internalised food objects and disposal of indigestible wastes are reviewed, along with production and control of the feeding current. The electrophysiology of the conduction system coordinating flagellar arrests is described. The review covers salient features of hexactinellid ecology, including an account of habitats, distribution, abundance, growth, seasonal regression, predation, mortality, regeneration, recruitment and symbiotic associations with other organisms. Work on the recently discovered hexactinellid reefs of Canada's western continental shelf, analogues of long-extinct Jurassic sponge reefs, is given special attention. Reproductive biology is another area that has benefited from recent investigations. Seasonality, gametogenesis, embryogenesis, differentiation and larval biology are now understood in broad outline, at least for some species. The process whereby the cellular early larva becomes syncytial is described. A final section deals with the classification of recent and fossil glass sponges, phylogenetic relationships within the Hexactinellida and the phylogenetic position of the group within the Porifera. Palaeontological aspects are covered in so far as they are relevant to these topics.

Transport Pathways in the Neotropical Sponge Aplysina.

Strands of cells distinct from the rest of the tissue were found running lengthwise through the endosome of four species of the sponge Aplysina. Although the strands were more highly pigmented than the adjacent tissue and could be removed intact with forceps, ultra-structural studies revealed no obvious barrier separating the cells in the strands from the rest of the tissue. The strands consist of stretches of elongate cells tightly aligned along densely bundled collagen fibrils, and areas of other elongate cells that possess numerous filopodia. When sponges were fed fluorescent latex beads in situ, beads were taken up and transported specifically into the strands; eventually they were found at the tip of the sponge and further down the stalk, away from the site of feeding. Beads injected into endosomal strands were also transported upwards in the strands to the tip of the sponge. Video microscopy of cells in strands that had been exposed along a portion of their length showed no bulk movement of cells; but individual cells were seen moving in both directions along the strands at 0.025-0.04 {mu}m.s-1. The endosomal cell strands are suggestive of a primitive nutrient transport pathway in sponges.

Porifera: sudden sperm release by tropical Demonspongiae.

Three tropical marine demosponges inhabiting the deep coral reefs of Jamaica expel immense clouds of milky fluid from exhalant apertures. Analysis of samples shows this fluid to contain mature male gametes. The behavior is an individual or a population event in different species.