[No abstract given, the work begins as follows] The subject of this paper is the imperfect vertebra of a large Ichthyopterigian, referable, I believe, to Ichthyosaurus australis, McCoy. The original was brought under my notice by the Rev. M. Kirkpatrick, of Bega, N.S. Wales, who obtained it from Marathon, Central Queensland. With his permission a cast was taken for the Australian Museum Collection. As Sir F. McCoy's description was very brief, an extended notice of one of the middle trunk, or anterior pre-caudal vertebrae, may be acceptable to Australian investigators.