The text discusses the economic importance of pelagic Coelenterates, which are significant as a food source and can cause harm to marine life. These organisms are common in the diets of small fish and can dominate plankton populations, leading to "red water" events that threaten the health of bottom-dwelling animals. The text also critiques some errors in a memoir by Prof. Kofoid, including mislabeling in a phylogenetic diagram and incorrect figure references. Despite these issues, the memoir is praised for its comprehensive coverage of species, synonyms, and history, making it an essential reference for researchers. The second part of the text is a review of "A Treatise on Probability" by J. M. Keynes. Keynes analyzes the principles of probability and the judgments involved in its application. He argues that probability measures the relevance of knowledge to a proposition without implying proof or disproof. Keynes rejects the traditional view that probabilities can be expressed numerically, stating that probabilities cannot be arranged in a one-dimensional series. He also critiques the principle of insufficient reason, modifying it to exclude cases where propositions can be expressed as disjunctions of mutually inconsistent propositions. Keynes rejects the view that exhaustive and mutually exclusive alternatives should each have a probability of 1/2, arguing that this leads to contradictions. The review concludes that Keynes' work is thorough and valuable, though some of his conclusions are considered exaggerated. The text also discusses the frequency definition of probability, which is rejected as it does not provide a basis for induction. The review praises the book's clarity and thoroughness, despite minor issues like misattributing Whitehead and Russell's work.The text discusses the economic importance of pelagic Coelenterates, which are significant as a food source and can cause harm to marine life. These organisms are common in the diets of small fish and can dominate plankton populations, leading to "red water" events that threaten the health of bottom-dwelling animals. The text also critiques some errors in a memoir by Prof. Kofoid, including mislabeling in a phylogenetic diagram and incorrect figure references. Despite these issues, the memoir is praised for its comprehensive coverage of species, synonyms, and history, making it an essential reference for researchers. The second part of the text is a review of "A Treatise on Probability" by J. M. Keynes. Keynes analyzes the principles of probability and the judgments involved in its application. He argues that probability measures the relevance of knowledge to a proposition without implying proof or disproof. Keynes rejects the traditional view that probabilities can be expressed numerically, stating that probabilities cannot be arranged in a one-dimensional series. He also critiques the principle of insufficient reason, modifying it to exclude cases where propositions can be expressed as disjunctions of mutually inconsistent propositions. Keynes rejects the view that exhaustive and mutually exclusive alternatives should each have a probability of 1/2, arguing that this leads to contradictions. The review concludes that Keynes' work is thorough and valuable, though some of his conclusions are considered exaggerated. The text also discusses the frequency definition of probability, which is rejected as it does not provide a basis for induction. The review praises the book's clarity and thoroughness, despite minor issues like misattributing Whitehead and Russell's work.