CARNIVOROUS SPONGES

EXTREMELY food-poor environments, such as the deep sea, place extraord inary demands on organisms with respect to feeding, resulting in modif ications of the feeding strategies found in shallow waters. A general rule is that macrophagy becomes a better strategy than microphagous su spension-feeding(1-3). The characteristics by which phyla are defined, nonetheless; remain unchanged in these adaptations. We present here a n apparently unique example of a fundamentally different body plan, de rived from a pre-existing phylum, occurring in deep-sea sponges. We de monstrate that the Cladorhizidae have evolved carnivory and capture sm all crustaceans by means of filaments provided with raised hook-shaped spicules. This adaptation to a food-poor deep-sea environment has res ulted in the loss of the diagnostic characteristics of the phylum Pori fera: an aquiferous system and choanocytes.