The Harderian glands, located within the orbital cavities of amphibia, reptiles, birds and most mammals, are perhaps one of the last discrete tissues for which we connot yet define a normal physiological role or regulation. The book brings together all known information on the Harderian glands. It covers comparative anatomy at several levels, the concentra- tions and regulation of indole and catecholamines, porph- yrins, peptides and lipids, and the interactions of the Har- derian glands with the thyroid and pineal glands. One chap- ter is devoted to the avian Harderian glands and their role...