The originality of this volume is to reveal to the reader the fascination of some unfamiliar sensory organs that are sometimes ignored and often misunderstood. These receptors have only recently been identified and their functional specificity is in some cases still a matter for discussion. The four classes of sensory organs considered here differ widely from one another in many respects. One might even say that the only thing they have in common is that they belong to cold-blooded vertebrates. These classes are: 1. the directionally sensitive lateral-line mechanoreceptors of fishes and amphi...