Dicyemennea canadensis n. sp. is described from a bathyal octopus collected off Canada in the Bay of Fundy. The dicyemid is a small species that rarely exceeds 600 microm in length. The vermiform stages are further characterized as having 17-23 peripheral cells, a conical-shaped calotte, an axial cell that extends to the base of the propoplar cells, and no abortive axial cells. Infusoriform embryos consist of 37 cells. There is 1 nucleus in each urn cell, and refringent bodies are absent. This is the first dicyemid to be described from the cephalopod Bathypolypus arcticus (Prosch. 1847), and the first dicyemid reported from Canada. In addition, it is the first species of Dicyemennea from the northwestern Atlantic Ocean to be described.