NEUROLOGY 96 Of Branchiostoma, 96--Spinal chord, 96--Brain, its size, 97--Brain of Osseous fishes, 97--of Ganoids, 98--of Chondropterygians, 100--of Cyclostomes, 101--Spino-cerebral nerves, 103--Spinal nerves, 107--Sympathic system, 108. CHAPTER VII. THE ORGANS OF SENSE 109 Smell, 109--Sight, 111--Hearing; connection of the ear with the air-bladder, 116--Taste, 119--Touch, 120. CHAPTER VIII. THE ORGANS OF NUTRITION AND DIGESTION 121 Food and mode of feeding, 121--Buccal and abdominal cavities and their openings, 123--Mouth and tongue, 123--Forms, texture, and arrangement of teeth, 124--Intestinal tract, 127--Liver, 132--Pancreas, 133--Spleen, 133. CHAPTER IX. ORGANS OF RESPIRATION 135 Respiration, 135--Structure and arrangement of the gills, 136--Pseudobranchiæ, 140--Accessory respiratory organs, 142--Air-bladder; its varieties, structure, and functions, 142. CHAPTER X. ORGANS OF CIRCULATION 150 CHAPTER XI. URINARY ORGANS 155 CHAPTER XII. ORGANS OF REPRODUCTION 157 Fishes are dioecious, 157--Hermaphroditism, 157--Oviparous and viviparous fishes, 157--Generative organs of Branchiostoma, 157--of Cyclostomes; their ova, 158--Female organs of Teleosteans and their ova, 158--Instances of females taking care of their progeny, 160--Male organs of Teleosteans, 162--Instances of males taking care of their progeny, 163--Generative organs of Ganoids, 163--of Chondropterygians and their ova, 166. CHAPTER XIII. GROWTH AND VARIATION OF FISHES 170 Changes of form of the body or certain parts, normally accompanying growth, 170--Changes dependent on sexual development, 176--Secondary sexual differences, 176--Mixogamous, polygamous, and monogamous fishes, 177--Hybridism as a cause of variation, 178--Regular and irregular growth of fishes, 178--Leptocephali not a normal state of development, 179--Changes of colour of the muscles and external parts; chromatophors, 182--Albinism, 183. CHAPTER XIV. DOMESTICATED AND ACCLIMATISED FISHES, ETC. 185 Domesticated fishes, 185--Acclimatisation of fishes, 185--Artificial impregnation of ova, 186--Tenacity of life, 186--Reproduction of lost parts, 188--Hybernation, 188--Useful fishes, 189--Poisonous fishes, 189--Poison-organs, 190.