title: Ultrastructure of elasmobranch lymphoid tissue. 1. Thymus and spleen.
mesh_terms: D000818:Animals; D005399:Fishes; D008214:Lymphocytes / Q000648:ultrastructure; D008221:Lymphoid Tissue / Q000648:ultrastructure*; D009132:Muscles / Q000648:ultrastructure; D010950:Plasma Cells / Q000648:ultrastructure; D013154:Spleen / Q000648:ultrastructure*; D013950:Thymus Gland / Q000648:ultrastructure*