Abstract: The Bovinae fauna of the Middle Sinap consist of Palaeoreas forachyceras Ozansoy, Palaeoreas elegansOzansoy. Palaeoreas lindermayeri Gaudry is unknown in this locality. The representataive of the Bovinae of the MiddleSinap, Palaeoreas braelıyceras Ozansoy was found in the lower part of the Middle Sinap series, is older thanPalaeoreas elegans Ozansoy. There are many different points on the morphological, biometrical, the cross-section ofthe base, the tip of horn-cores of Palaeoreas braehyeeras Ozansoy, Palaeoreas elegans Ozansoy., In addtion, thereare also different turning form of the horn-cores of Palaeoreas brachyeeras Ozansoy, Palaeoreas elegans Ozansoy. Theconcavities of the inside - outside of the horn-cores of Palaeoreas bracnyeeras Ozansoy are deeper than Palaeoreaselegans Ozansoy. First studying about the biometrical, graphical on the materials of the species of Palaeoreas hadbeen made to me. Thus, it will be possible to find the evolutive forms of the species of Palaeoreas.