title: Serological studies of two hybrid sea urchins.
mesh_terms: D000818:Animals; D000937:Antigen-Antibody Reactions; D000941:Antigens / Q000032:analysis*; D004447:Echinodermata; D004622:Embryo, Mammalian / Q000276:immunology*; D004625:Embryo, Nonmammalian; D006168:Guinea Pigs; D006824:Hybridization, Genetic; D007106:Immune Sera; D005779:Immunodiffusion; D007122:Immunoelectrophoresis; D010323:Passive Cutaneous Anaphylaxis
chemical_list: D000941:Antigens; D007106:Immune Sera