title: The development of immunological capacity in phylogenetic perspective.
mesh_terms: D000663:Amphibians; D000818:Animals; D005075:Biological Evolution; D004524:Eels; D005399:Fishes; D006413:Hematopoietic System / Q000166:cytology; D007109:Immunity; D008198:Lymph Nodes / Q000166:cytology; D008208:Lymphatic System / Q000254:growth & development / Q000276:immunology* / Q000502:physiology*; D009893:Opossums; D012754:Sharks; D013950:Thymus Gland / Q000166:cytology