olume V of this treatise is concerned with sensory systems and some aspects of function of the central nervous system. Sensory systems have been extensively studied in fish not only because of a wide general interest in the behavioral and sensory physiology of this group but also because, in many instances, fish are technically suitable for general studies of sensory systems and have certain receptors not present in other groups. Electro-receptors fall into this category; these receptors are unique to fishes, and studies of this system have application to receptor function in general. Volume V: 1-Vision: Visual Pigments 2-Vision: Electrophysiology of the Retina 3-Vision: The Experimental Analysis of Visual Behavior 4-Chemoreception 5-Temperature Receptors 6-Sound Production and Detection 7-The Labyrinth 8-Mechanoreceptors: The Lateral Line Organ Receptors Ake 9-Electroreception 10-Electric Organs.

The endocrinology of fishes is considered in Volume II. Few fields of animal physiology have expanded more rapidly during the past decade. The publication in 1957 of "The Physiology of the Pituitary Gland of Fishes" (New York Zoological Society) by Grace E. Pickford and J. W. Atz provided a detailed bibliography and review of all the significant earlier work on the endocrinology of fishes; the authors of this comprehensive book dealt not only with the pituitary but with other endocrine systems related to it. The intervening years have seen intense research in fish endocrinology, resulting in numerous monographs and reviews devoted to particular subjects and increasing numbers of fish papers in General and Comparative Endocrinology which first appeared in 1961. New factors, such as some of the neurohypophysial hormones, have been discovered in previously known endocrine organs; additional functions, such as those of prolactin, have been described for previously known hormones; new hormones, such as calcitonin, have been recognized in tissues (the ultimobranchial glands) which only a decade ago were not accepted as endocrine organs. This has been an exciting period in comparative endocrinology, and the aquatic vertebrates with their vast range of specialized functions have held the key to several significant discoveries-particularly those of phylogenetic interest. Volume II: 1-The Pituitary Gland: Anatomy and Histophysiology 2-The neurohypophysis 3-Prolactin (Fish Prolactin or Paralactin) and Growth Hormone 4-Thyroid Function and Its Control in Fishes 5-The Endocrine Pancreas 6-The Adrenocortical Steroids, Adrenocorticotropin and the Corpuscles of Stannius 7-The Ultimobranchial Glands and Calcium Regulation 8-Urophysis and Caudal Neurosecretory System.

The major portion of this fourth volume is devoted to a review of aspects of respiration, circulation, and properties of the blood in fishes. There is a chapter on the role of the swim bladder as a hydrostatic organ and another on the effects of hydrostatic pressure on animal function. The swim bladder presents a fascinating example of the special organization of the circulatory system to meet a particular functional demand, in this case the secretion of gases against large concentration gradients. Some recent developments in the understanding of how gases are secreted into the swim bladder are reported. Volume IV: 1- Anatomy and Physiology of the Central Nervous System 2-The Pineal Organ 3-Autonomic Nervous Systems 4-The Circulatory System 5-Acid-Base Balance 6-Properties of Fish Hemoglobin 7-Gas exchange in fish 8-the regulation of breathing 9-Air Breathing in Fishes 10-The Swim Bladder as a Hydrostatic Organ 11-Hydrostatic Pressure 12-Immunologyof Fish.