Ordovician stromatoporoids from Tasmania

Ordovician sponges from west-central and east-central Alaska and western Yukon Territory, Canada

“…Cliefdenella Webby, 1969, andRigbyetia Webby &Lin, 1988, have somewhat similar internal skeletal structures of vertical incurrent and excurrent tubes and vesiculae, but their growth forms are quite different. Cliefdenella, as shown here (Fig.…”

Treatise Online no. 41: Part E, Revised, Volume 4, Chapter 16B: Labechiida

“…d, longitudinal section showing vanelike, vertical pillars (some parts of plates being intersected at right angles, others obliquely or near parallel to individual plates, and in these latter areas, traces of tiny, parallel spines may be seen inclined upward and outward away from the pillar centers to about 25 degrees; also in places, well-defined, spar-filled denticles are exhibited on tops of cyst plates, and the spar-replaced cyst plates also seem to have been disrupted (perhaps even perforated) in places, ×10 (Webby, 1979b, fig. 5E).…”

“…radiostroma WeBBy, 1979b, p. 208 (Webby, 1979b, fig. 5B); b, tangential section showing pillars are formed of four or five short, radiating, vanelike plates that may be fused near axis to give a stellate outline (Webby, 1979b, fig. 5D); c, tangential section showing complex pillars with their outwardly radiating, vanelike plates, but also in places, one or two concentrically arranged, closely spaced cyst plates intersect these vanelike plates, producing centers with fine meshworks of tiny, complete and incomplete, polygonal spaces, ×5 (Webby, 1979b, fig.…”

Treatise Online, no. 25: Part E, Revised, Volume 4, Chapter 9B: External morphology of the Paleozoic Stromatoporoidea: Shapes and growth habits

“…Some stromatoporoids, like many labechiids, do not show to grow, while the laminar growth units appear to have been disrupted at least twice by sediment incursions, ×2.5 (Webby, Zhen, & Percival, 1997, pl. 2C); 2, longitudinal section illustrating that initial cystose growth of specimen developed over a relatively flat laminar base, then columnar growth took over as successive, large axial cyst plates were added to the column, ×2.5 (Webby, new); 3, longitudinal section of skeleton also formed on a relatively flat laminar base, and again lower-lying laminar units appear to have been disrupted a number of times by sediment influxes, while broadly raised columnar area to left maintained a continuity of growth, ×2.5 (Webby, new); 4, tangential section showing columnar nature of vertical growth, ×2.4 (Webby, new); 5, longitudinal view illustrating remarkable continuity of a vertical column relative to lateral growth; note pattern of lateral extensions initially draping off main column, perhaps because sediment was already piled up against rapidly upgrowing column, ×0.75 (Webby, new); 6, longitudinal section, Pachystylostroma surculum WeBBy, holotype, PMO 97112, Mjøsa Limestone, Bergevika, Norway, showing strongly mamelate nature of large domical skeleton, especially close to its upper surfaces, where many sediment-filled inclusions seem to occur; with respect to near-surface growth of such skeletons, they may be described also as locally digitolaminar, ×3.5 (Webby, 1979, fig. 2C).…”