Morphogenetic processes and seasonal changes in the anatomic and histological organization of the Barents Sea sponge Halichondria panicea (Pallas)

As a result of histological investigations of seasonal dynamics in the anatomical-tissue organization of the litoral sponge Halichondria panicea (Pallas), morphogenetical processes during different periods of its life cycle are described in detail. Correlations between different phases of sexual reproduction and conditions of anatomical and tissue organization in the maternal organism are stated. It is noted that tissue reduction of the definitive sponge Halichondria panicea during autumn--winter season is a natural phenomenon, regularly repeating in the life of the litoral sponge investigated, as a result of the maternal organism's "exhaustion" in the period of sexual embryogenesis.