title: When size matters.
authors.forename: Marvin L
authors.initials: ML
authors.lastname: Hackert
authors.forename: Austen F
authors.initials: AF
authors.lastname: Riggs
mesh_terms: D000818:Animals; D006454:Hemoglobins / Q000737:chemistry*; D009835:Oligochaeta / Q000378:metabolism*; D020836:Protein Structure, Quaternary
chemical_list: D006454:Hemoglobins; C064665:erythrocruorin