Mr. Whiteaves in his description of this species mentions that “in one specimen there are indications of what looks like a short break or separation between the anterior and posterior portions of the dorsal (or between the two dorsals if there were two, which is scarcely probable), but this break may be owing to an accidental and abnormal fracture of the fin rays at this point, for in other specimens the two portions appear to be continuous.” This break is, however, represented in all his figures, including the restored sketch given in his second paper in the Transactions of the Royal Society of Canada.