All larvae are covered to varying degree with flagellated cells, which provide their principal means of locomotion. Sponges have a remarkable capacity for regeneration, and asexual budding is frequently a response to damage. Broken fragments of an adult sponge can regenerate by a complete reorganisation of body tissue, and grow into new sponges. This regenerative process is known as somatic embryogenesis . The majority of sponges house both sperm and egg cells within the same adult.
Choanocytes can transform to become male sex cells, or oocytes.
These sponges have a body composed of calcium carbonate spicules. Calcareans come in a variety of forms, including asconoid, sycanoid and leucanoid. Spicules may be straight or composed of three or four rays. The majority of calcareous sponges are rather small and drab, with large choanocytes. Leucosolenia - a small, shallow water species.