Classification of Leucosolenia
Phylum :- Porifera (Pore bearing, cellular grade, asymmetrical or radially symmetrical).
Class :- Calcarea (Calcareous spicules present).
Order :- Homocoela (Canal system of ascon type).
Genus :- Leucosolenia
Habit and habitat
Marine colonial sponge found in shallow waters below tidemark on seashore rocks, having intense wave action of the water.
Distribution
Distributed from Matha’s vineyard to Gulf of St. Lawrence. From Casco bay to Arctic ocean and common in Europe.
Comments on Leucosolenia
- Colony is composed of bunches of whitish vertical cylinders and tubes about 25 mm long.
- Vertical tubes of the colony contain osculum distally. They are joined together by horizontal tubes at the base. The surface of the body is perforated by numerous pores or ostia or incurrent pores.
- Magnified portion of the colony shows vase-shaped individuals, inhalent ostia, tri-radiate spicules and horizontal branches attached to substratum.
- Simplest sponge with ostia ~ spongocoel ~ osculum arrangement of water current. Canal system is simplest of ascon type. Osculum is surrounded by oscular fringe.
- Body wall is composed of dermal epithelium forming outer layer, and Choanocyte layer forming inner layer, separated by middle mesenchyme layer.
- Calcareous spicules are monaxon or Triaxon.
- Asexual reproduction by budding, branching and regeneration.
- Sexual reproduction by ova and spermatozoa. Larva is parenchymula.
- Leucosolenia has phylogenetic significance because complex sycon and leucon sponges pass through ascon stage during their development.
Identification
Since the above specimen contains oscula, ostia, anastomosing colony and all above characters and hence it is Leucosolenia.
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