FIGURE 10. Tretodictyum amchitkensis n in <strong>New glass sponges (Porifera: Hexactinellida) from deep waters of the central Aleutian Islands, Alaska</strong>

FIGURE 10. Tretodictyum amchitkensis n. sp., body and framework. A. Frame grab from video footage of the holotype in situ before collection, laser spacing 10 cm. B. Three largest dried fragments, one on left in top and side views. C. Dry external dermal surface showing ridges and grooves. D. Dry internal atrial surface showing open exhalant apertures. E. Closer view of dry dermal surface showing quadrangular spicule lattice over inhalant canals. F. Closer view of dry atrial surface showing uncovered exhalant aperture and dense spicule felt-work. G. Close view of wet atrial surface showing tissue ring around exhalant canal aperture. H. Cleaned marginal skeletal framework showing branching of vertical septa. I. Closer view of septa and intervening space showing transverse connecting strands. J. Marginal end of one septum in lateral view showing disposition of longitudinal strands (SEM). K. Dermal surface of older framework 5 cm from margin with thin surface cortex (SEM). L. Atrial surface of older framework 5 cm from margin with thin surface cortex (SEM).