Observations On Polyzoa: Sub-Order Phylactolaemata is a scientific book written by Alpheus Hyatt, first published in 1868. The book is focused on the study of Polyzoa, a group of aquatic invertebrates that are commonly found in freshwater habitats. Specifically, the book focuses on the sub-order Phylactolaemata, which includes several species of freshwater bryozoans. The book is divided into several chapters, each of which covers a different aspect...