A guide to the fossil invertebrate animals in the Department of geology and palaeontology in the British museum (Natural history) . FiG. 12.—Fossil sponge spicules: Silicispongiae, Tetractinellida. Skeletalspicules of Lithistida. Rhizomorina: a, b, Seliscothon; c, Cnemidia-strum. Tetracladina : d, Aulocopiimi megamorma; e, /, Doryderma;g, Carterella. Eutaxicladina: h, Astylospongia. a, b, c, d, h, enlarged40 diam.; e, 26 diam.; /, g, 20 diam, (After Hinde.). Fig. 13.—Fossil sponge spicules : Silicispongiae, Tetractinellida. Skeletal((X-e) and dermal (f-i) spicules of Lithistida. Eutaxicladina:
A guide to the fossil invertebrate animals in the Department of geology and palaeontology in the British museum (Natural history) . FiG. 12.—Fossil sponge spicules: Silicispongiae, Tetractinellida. Skeletalspicules of Lithistida. Rhizomorina: a, b, Seliscothon; c, Cnemidia-strum. Tetracladina : d, Aulocopiimi megamorma; e, /, Doryderma;g, Carterella. Eutaxicladina: h, Astylospongia. a, b, c, d, h, enlarged40 diam.; e, 26 diam.; /, g, 20 diam, (After Hinde.). Fig. 13.—Fossil sponge spicules : Silicispongiae, Tetractinellida. Skeletal((X-e) and dermal (f-i) spicules of Lithistida. Eutaxicladina: a,Mastosia. Anomocladina : b, Cylindjophyma. Tetracladina : c, d,Callopegma; e, Plinthosella. e, enlarged 26 diam.; the rest 40 diam.(After Hinde.) cladina (Fig, 13 &); Cylindrophyma is common in UpperJurassic rocks. Megamorina (Silurian to Eecent) : desmasrelatively large, curved, branching rods, either intertwiningor joined as in Eutaxicladina (Fig. 12 e, f, g)\ Doryderma(Fig. 16 &) is abundant in the Upper Chalk. Rhizomorina(Cambrian to Eecent) : desma small, usually elongate, curved,with irregular branches; these end in minute facets, which 38 GUIDE TO THE FOSSIL INVEETEBEATE ANIMALS. Gallery X. are closely apposed to the axis and branches of adjoiningspicules so as to form loosely arranged fibres or an irregularmeshwork (Fig. 12 a, h); the Cretaceous Verruculina(Fig. 17) is characteristic. Sub-Class II. — monactinellida. Demospongia
Size: 2673px × 935px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorbr, bookcentury1900, bookdecade1900, booksubjectfossils
