Remains of the Anthropoid Apes are so rare among fossils, that every new specimen is worthy of special description and discussion. I therefore offer to the Society some account of the fourth known example of the mandible of Dryopithecus fontani , which has been kindly lent to me by Prof. Luis M. Vidal, of Barcelona. It was found by Señor José Colominas near Seo de Urgel, Province of Lérida (Spain), in a deposit usually ascribed to the Upper Miocene; and, as already observed by Prof. Vidal, the specimen is of unusual interest, on account of its occurrence in association with the Hipparion fauna. The jaws of the same species previously discovered in France, are from Middle Miocene formations; while the only traces of the great Apes of a later date hitherto found in Europe are a few teeth from the Bohnerz of Würtemberg and the well-known femur from the Sands of Eppelsheim (Hesse-Darmstadt). The new specimen (Pl. XLIV) comprises the greater part of the left mandibular ramus and the lower half of the symphysis, with the three molars well preserved and the roots of the fourth premolar broken in the socket. The pattern of the molars and the steepness of the symphysis determine the generic position of the fossil; while the proportions of the bone and the characters of the molar teeth are so closely similar to those of the specimens of D.fontani from the type-locality, that (as already recognized by Prof. Vidal) it can only be referred to this species.