In rabbits maintained for experimental purposes at this Department, there has been collected from the stomach on a number of occasions a nematode showing certain affinities with the genus Graphidium Railliet and Henry, 1909. The parasite in question, however, differs from the type species of that genus in characters which must be regarded of more than specific value and it has therefore been assigned to a new genus. It has only recently been noticed in our rabbits. I am indebted to Dr Smith for calling my attention to it. Whether the parasite had heretofore been overlooked in autopsy examinations or has been recently introduced cannot be said. It seems probable that it originated from a wild host and is indigenous to this continent. It was first noticed after our rabbits had been transferred to quarters where they had access to the ground.