Fossils in the University Museum, Oxford: I. On Silurian Echinoidea and Ophiuroidea

As the work of arranging the Geological Collections of the Oxford University Museum proceeds, much interesting material is brought to light. Some of this will be described from time to time; but as the descriptions will be undertaken by more than one observer, some advantage may be gained, if only in indicating the common source of the material, by bringing these contributions together under the title of ‘Fossils in the University Museum, Oxford’ In this communication I propose to treat of some Silurian Echinoidea and Ophiuriodea. The Family Eucladidæ. The interesting and remarkable fossil described by Dr. Woodward under the name of Eucladia Johnsoni has recently been placed by Dr. Gregory in a new family—the Eucladidæ, of which hitherto it has been the sole representative. We are now able to assign it companions, and to add to our knowledge of its structure, with the result, as I believe, of showing that a more fundamental distinction exists between this group and all other Ophiuroidea than between the two recognized subdivisions Ophiuræ and. Euryalæ. The family must be relegated at least to a new order, which may be called the Ophiocistia. Before proceeding further, it will be necessary to clear up certain doubtful points in the anatomy of Eucladia ,Johnsoni . The exposed surface of the fossil was described by Dr. Woodward as the ventral aspect, and good reasons were given for this proceeding, attention being called to the fact that ~he arms originate from it, and that it bears the madreporite. The