The Works of Francis Maitland Balfour, Volume 2 (of 4): A Treatise on Comparative Embryology: Invertebrates is the second volume in a large edition devoted to the work of the eminent British embryologist Francis Maitland Balfour. This book explores the comparative field of embryology, particularly the study of invertebrate development. The author carefully analyzes the stages of development of different groups of invertebrates, comparing their features and regularities. This book is an important contribution to the study of embryology and will help the reader to better understand the processes of development of living organisms.