[Development and structure of the lymphoepithelial pharyngeal ring in the Macacus rhesus].

The lymphoepithelial pharyngeal ring has been studied in fetuses and 6-8-month-old monkeys (Macacus rhesus) by means of macro- and microscopical methods. The pharyngeal, palatile and lingual tonsils and a poorly manifested laryngeal tonsil have been revealed. The anlage of the lingual tonsil occurs later than that of the other ones (in fetuses of 60-73 mm of the parietal-coccygeal length), when the palatile and pharyngeal tonsils are already inhabited with lymphocytes. By the end of the embryonal period, the main structural components are already formed in all the tonsils, but their functional activity is not yet manifested. During the postembryonic period certain differences are revealed in the tonsil structure, they are presented as the germinative centers formation, appearance of active macrophages and plasma cells. A close connection between the lingual, pharyngeal and laryngeal tonsils with the glandular tissue is noted.