An overview of the Mediterranean cave-dwelling horny sponges (Porifera, Demospongiae) Author Manconi, Renata Author Cadeddu, Barbara Author Ledda, Fabio Author Pronzato, Roberto text ZooKeys 2013 281 1 68 http://dx.doi.org/10.3897/zookeys.281.4171 journal article http://dx.doi.org/10.3897/zookeys.281.4171 1313-2970-281-1 Hexadella pruvoti Topsent, 1896 Fig. 39 Hexadella pruvoti Topsent, 1896: 120 (partim). Description. Growth form thinly encrusting and lobate, in large patches. Colour bright yellow in vivo, dark purple in alcohol after releasing a yellowish fluid. Surface finely conulose, entirely wrinkled by small evident collagenous reinforcements irregularly crossing and converging towards small conules, with inconspicuous inhalant apertures surrounding the tiny conules armed by debris. Large oscules in vivo, not visible after fixation in ethanol. Ectosome with bundles of collagen fibrils. Choanosome fragile with large clusters of spherulous cells with large inclusions of heterogeneous size, containing microgranules and microgranular cells. Choanocyte chambers (ca. 40 x 20 µm in diameter) eurypylous, densely packed with 40-60 choanocytes. Bacteria in the mesohyl. Aerophobins 1 and 2 compounds with medium-high natural toxicity. Habitat. Cave, rocky cliffs. Bathymetric range 10-35 m. Mediterranean caves. Blava, Blue, Misidacis caves (Balearic Sea); Corail Cave (Gulf of Lions); Trypia Spilia Cave (Aegean Sea) ( Marti et al. 2004 ; Turon et al. 2009 ; Reveillaud et al. 2010 , 2012 ; Pronzato and Manconi 2011 ; Gerovasileiou and Voultsiadou 2012 ).