Comparative Endocrinology: A Treatise in Two Volumes, Volume II, Part One: Invertebrate Hormones, Part Two: Tissue Hormones focuses on animal physiology, morphology, and chemistry and systematic and comprehensive explanation of endocrine principles from the comparative point of view. The selection first offers information on hormones controlling reproduction and molting in invertebrates and the structure of neurosecretory systems in invertebrates. Discussions focus on protozoa, crustacea, insects, and neurosecretory systems of the head, thorax, and abdomen. The text then ponders on bradykinin, angiotensin, and substance P and heparin. The publication examines physiologically active lipid anions and 5-hydroxytryptamine. Topics include biologically active unsaturated fatty acids without alcoholic hydroxyl groups, prostaglandin, endometrial acids in menstrual fluid, turnover rate, and biosynthesis and fate. The manuscript also tackles cholinergic neurohormones and adrenergic neurohormones. The selection is a dependable source of data for readers interested in invertebrate and tissue hormones.