TWELVE FIGURES Polyodon spathula, popularly called Spoonbill and Paddlefish, is one of the most individualistic and interesting representatives of the living Ganoids. Among the striking external features are hundreds of groups of black spots on both the dorsal and ventral surface (excepting a narrow area along the mid-dorsal and midventral line) oi the bill. The spots of a group may be arranged in two to five, or more, clearly marked smaller, primary groups of two to ten individual dots. Now

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... then a single spot is located quite apart from others. As a qule the spots are grouped in the area corresponding to or lying over the meshes of the bony network of the bill. They rarely lie immediately over a plate of bone. Figs. 1, 2 , 3 , 4 will give a better idea of the arrangement and distribution of these spots on the bilkof Polyodon than can be gained from a description. Similar groups of spots are found on the outer surface of the operculum, about the eye and other re gions of the head. Their distribution on the operculum and side of the head is shown in fig. 5 . A large group may contain as many as sixty dots, but as a rule a group contains less than half that number, particularly on the bill. The largest groups have been found on the operculum. There is, however, considerable insignificant variation among the individuals in both the size of the groups and their distribution on the operculum and other parts of the head. On the bill the size of the groups of spots and their distribution are more or less determined by the bony network of the bill. Figs. 1 and 2 show their distribution on a large