Аннотация:THE STRUCTURE OF THE PROBOSCIS APPARATUS IN THE PARASITE OF THE SALMON SHARK CESTODE NYBELINIA SURMENICOLA (TRYPANORHYNCHA)Biserova N.M., Margarit A.A.M.V. Lomonosov Moscow State University, Moscow, RussiaSummary. The ultrastructure of the proboscis, proboscis sheaths and muscular bulbs of N. surmenicola was studied. Differences in the organization and a common features were revealed. The tentacle wall has a symplastic myoepithelial nature, the fibrillar extracellular wall of the tentacle sheath is formed by myocytes and fibroblast-like cells; the tentacle retractor has a smooth muscle mesenchymal nature, while the musculature of the bulbus is represented by striated muscle tissue found in the attachment organs of some other cestodes. The homology of Trypanorhyncha proboscis apparatus still remains one of the unsolved problems in the evolution of cestodes. Key words: ultrastructure; myoepithelium; rhynchocoel; extracellular matrix
