title: Colonization of the thymic primordium by migratory lymphocytoblasts in amphibian embryos.
mesh_terms: D000818:Animals; D001001:Anura; D002454:Cell Differentiation; D002465:Cell Movement; D006412:Hematopoietic Stem Cells / Q000166:cytology; D008214:Lymphocytes; D011894:Rana pipiens / Q000276:immunology*; D013950:Thymus Gland / Q000196:embryology* / Q000637:transplantation