17 amino acids (AA) were determined in adult specimens of the tapeworm Ligu
la intestinalis, from the intestine of cormorant (Phalocrocorax: carbo). In
comparing the AA values in adult tapeworms with those in plerocercoids fro
m the body cavity of various fishes, in adult tapeworms statistically highl
y significantly higher values were found in threonine, valine, tyrosine, ph
enylalanine, lysine, aspartic and glutamic acids, proline and alanine. An e
xtremely high increase of the values in lysine and phenylalanine suggests a
n important role of these AAs in the protein synthesis at maturation, sexua
l organ development and egg production in this tapeworm species.