The Lymnaeidae (also known as ‘pond snails’) are a species-rich and globally distributed family of freshwater snails, many species of which are known to be hosts of parasitic trematodes (such as the liver fluke, Fasciola hepatica). Written by world-leading experts in the field, this book covers a wealth of topics ranging from the phylogeny and taxonomy of lymnaeid snails to their relationships with helminths and their impact on public and veterinary health. It provides an overview of the species richness, evolution, ecology, biogeography and fossil record of the family. A considerable number of chapters are devoted to the economic and medical importance of lymnaeids, their involvement in the transmission of fascioliasis and other zoonotic diseases. Special chapters deal with the molecular and morphological identification of the Lymnaeidae, their rearing in the laboratory and experimental approaches to their study.

Tree shrews are small-bodied, scansorial, squirrel-like mammals that occupy a wide range of arboreal, semi-arboreal, and forest floor niches in Southeast Asia and adjacent islands. Comparative aspects of tree shrew biology have been the subject of extensive investigations during the past two decades. These studies were initiated in part because of the widely accepted belief that tupaiids are primitive primates, and, as such, might provide valuable insight into the evolutionary origin of complex patterns of primate behavior, locomotion, neurobiology, and reproduction. During the same period, there has been a renewed interest in the methodology of phylogenetic reconstruction and in the use of data from a variety of biological disciplines to test or formulate hypotheses of evolutionary relationships. In particular, interest in the com­ parative and systematic biology of mammals has focused on analysis of phy­ logenetic relationships among Primates and a search for their closest relatives. Assessment of the possible primate affinities of tree shrews has comprised an important part of these studies, and a considerable amount of dental, cranio­ skeletal, neuroanatomical, reproductive, developmental, and molecular evi­ dence has been marshalled to either corroborate or refute hypotheses of a special tupaiid-primate relationship. These contrasting viewpoints have re­ sulted from differing interpretations of the basic data, as well as alternative approaches to the evolutionary analysis of data.

This book, like the two previous editions, was written as an introduction to human cytogenetics, but it could also be used as a text for a general cytogenetics course, since chromosome structure and behavior are similar in all eukaryotes. Many examples in this book are from organisms other than humans, reflecting our combined backgrounds of molecular and bacterial genetics, and plant and animal cytogenetics. In the rapidly expanding field of human cytogenetics, certain subjects, for instance clinical and cancer cytogenetics, are now covered in recently published, thousand-page volumes. In this book, such subjects are presented only in outline. The enormous growth of information has also made the choice of topics and of examples to illustrate them even more arbitrary and subjective than in the previous editions. Apart from a few pages here and there, the text has been rewritten. Major parts, especially those on molecular matters, have been added. This book would not exist without the dedicated participation of Mrs. Barbara Susman. She has been involved in the project from the planning stages to the final proofreading. She has done the extensive literature research, designed most of the tables and illustrations, and edited and typed the text. For discussions and suggestions we are indebted to many colleagues. We wish especially to mention Drs. Lassi Alvesalo, Evelyn M. Kuhn, and Renata Laxova, who have critically read selected parts of the book, and Dr. Carter Denniston, who has read the whole text.

human kind cannot bear very much reality. T. S. ELIOT, Four Quartets When I was a little child, I lived in an old and somewhat rickety house by the sea. When the winter wind blew, the house would shake and tremble, and cold drafts would whistle through cracks in the walls. You might have thought that lying in bed in a dark room on such cold, windy nights would have frightened me. But it had just the opposite effect: having known this en­ vironment since birth, I actually found the shaking of the house, the whistling of the wind, and the crashing of the sea to be comforting, and I was lulled to sleep by these familiar sounds. They signaled to me that all was right with the world and that the forces of nature were operating in the normal way. But I did have a problem. On the dimly lit landing of the staircase leading up to my bedroom, there was a large and dark picture of a male lion, sitting as such lions do with his massive paws in front of him and his head erect, turned slightly to the right, and staring straight out at you with yellow blazing eyes. I had great difficulty getting past that lion. Someone would have to hold my hand and take me up to bed, past the dreaded picture.