Immune system in a monotreme: studies on the Australian echidna (Tachyglossus aculeatus).
D000818:Animals; D000917:Antibody Formation; D001065:Appendix / Q000033:anatomy & histology*; D008198:Lymph Nodes / Q000033:anatomy & histology*; D008322:Mammals / Q000033:anatomy & histology* / Q000276:immunology*; D013154:Spleen / Q000033:anatomy & histology*; D013950:Thymus Gland / Q000033:anatomy & histology*