Observations On Polyzoa: Sub-Order Phylactolaemata is a book written by Alpheus Hyatt and published in 1868. The book is a comprehensive study of the Phylactolaemata sub-order of Polyzoa, a group of aquatic invertebrates that form colonies. The book covers the morphology, anatomy, and reproductive biology of the Phylactolaemata, as well as their ecology and distribution. Hyatt's observations are based on extensive research and examination of specimens...