There is but little information available regarding the helminthology of the California coast; therefore the following account of some cestodes found in gulls of this region may be of interest. Sixty-six birds were examined, fifty-six of which contained one or more parasites, an infection of 84.8o%. The worms have been examined in both fresh and preserved material, in whole mounts and sections. The fixatives employed were alcoholic-sublimate-acetic and alcoholic Bouin, with a few specimens fixed in 10%o formalin. The stains used were aceto-carmine and Ehrlich's hematoxylin for whole mounts, and for sections the latter and iron alum hematoxylin. All measurements in this paper are expressed in mm. and were made on preserved material except as stated in the text.