Dendy and Row, 1913
Definition: Clathrinida with tubular, ramified or even anastomosed cormus either with many oscula, or individualized with a large atrium and a single osculum. The sponge wall is composed of a distinct cortex and choanosome. The skeleton of the choanosome and the atrial wall is absent or composed of small and dispersed triactines and tetractines (Calcinean evolution).
Remarks: Four genera are recognized, one of which (Leucettusa ) is not represented in the area.
Source: Borojevic et al., 1990.
Genera represented in the area:
Ascandra Haeckel, 1870 (type species: A . falcata Haeckel, 1870): choanoderm forms folds inside the choanocoel isolating radially arranged spaces in the form of shallow cavities or true radial tubes; choanosomal folds are sustained by apical rays of external tetractines.
Leucaltis Haeckel, 1870 (type species L . clathria Haeckel, 1870): body composed of large, ramified and anastomosed tubes. Each tube has a distinct cortex, a choanoderm composed of elongated and ramified choanocyte chambers and a central atrium. The choanoderm and the atrial wall have a secondary skeleton composed of small triactines and tetractines.
Leuclathrina Borojevic and Boury-Esnault, 1987 (type species L . asconoides Borojevic and Boury-Esnault, 1987): leuconoid aquiferous system; the skeleton is restricted to the cortex, and the choanosome lacks spicules completely.
Species included:
Ascandra falcata
Leucaltis clathria
Species not treated here:
Leuclathrina asconoides Borojevic and Boury-Esnault, 1987, Bay of Biscay, 500-760 m.