The remarkable fossil fish which forms the subject of the present communication belonged originally to the late Mr Powrie of Reswallie, and was acquired, along with the rest of his collection, by the Edinburgh Museum in 1892.The specimen was obtained by Mr Powrie in a quarry of the Lower Old Red Sandstone at Turin Hill, near Forfar.In his monograph on the Fossil Cephalaspidœ of Great Britain, published in 1870, (p. 41), Professor E. Ray Lankester refers in the following terms to the specimen in question:—“A very remarkable specimen of shagreen-like structure has been discovered by Mr Powrie in Forfarshire, in beds which have furnished Cephalaspis. As I have not been able to assign it to Cephalaspidian fishes, though it may possibly, be connected with them, I only allude to it here. It consists of a surface covered with minute spinous tubercles, the whole having the appearance of a fossilised piece of shagreen, and its shape is more or less that of a Cephalaspid, with head and body.