In 1897 ('Zoologist,' p. 178) we drew attention in these pages to the first part of this great publication. Part II. has now appeared in the shape of another massive volume, bringing up the pagination to a total of 2183, the number of genera described to 798, while the described species are now no fewer than 2510.
In reading the descriptions of the gorgeous and bizarre colouration of many of these fishes, one cannot but feel that some of our speculations as to the meaning and service of animal colouration will have to be qualified by much apparently different piscatory evidence. How suggestive is the following account of the young of the Garabaldi (Hypsypops rubicundus), which are of a dusky scarlet, with intensely bright blue markings. "These brilliant little fishes inhabit only large, deep rocky pools, hiding under the seaweed of ledges, and frequently swimming out into the open water of the pool. They are accompanied by the adult, the usual uniform scarlet colour of which appears a distinct lustreless yellow in the water." The fish is common on the coast of California.
This is one of the monographs of the United States Geological Survey, and forms vol. xxx. of that series. As the author remarks: "To the biologist the suggestion of silicified Medusæ is a violent attack upon his previous conceptions of such organisms, and the possibilities of their preservation as fossils in any other manner than as faint impressions on fine limestone, sandstone, or shale." They, however, occur in a silicified condition, and have been found to belong to the Jurassic, Permian, and Cambrian faunas. Their mode of occurrence in the Middle Cambrian of Alabama "suggests at once the habit of living on a
