Fig. 6 in First record of chambered hexactinellid sponges from the Palaeozoic

Fig. 6. Chambered hexactinellid sponge Casearia devonica sp. nov., BSPG 2012 I 46c (holotype) from the Lower Emsian at Colle, Cantabrian Mountains, NW Spain. A. Detail of Fig. 5C; branch with irregularly-chambered structure, sectioned roughly parallel to growth direction and tangentially to dermal cortex. Upper chambers exhibiting seemingly irregular hexactinellid framework, which shows regular rectangular meshes in radial cross-sections (compare with Figs. 7 and 8A). B. Detail of A, showing tangentially-sectioned dermal cortex of small chamber (indicated by arrow), completely enclosed by considerably larger subsequent chamber. Triangular meshes of dermal cortex resulting from interconnecting, spherically-enlarged multiradiate nodes. C. Detail of lowermost chamber in A; tangential section showing enlarged nodes forming dermal cortex and producing triangular meshes (arrowed), and regular rectangular meshes directly below dermal cortex.