A new trypanorhynch cestode, Grillotia borealis sp. n., is described from the spiral intestines of softnose skates of the genus Bathyraja collected from subarctic waters of the North Pacific Ocean: B. parmifera (Bean) (type host), B. aleutica (Gilbert) and B. interrupta (Gill et Townsend) from the Bering Sea and B. minispinosa Ishiyama et Ishihara and B. smirnovi (Soldatov et Pavlenko) from the Sea of Okhotsk off Japan. The new species is distinguished from other species of Grillotia by possession of the following combination of characters: four hooks per principal row, hooks 4(4') distinctly separated from hooks 3(3') of principal row, principal rows separated by 13-15 intercalary hooks in 2-3 rows, hooks 2(2') and 3(3') change in form along their respective files, hooks 1(1') do not change in form along the file, a broad band of microhooks on the external tentacular face, intermediary hooks are lacking, absence of a special basal armature, origin of the retractor muscle near middle of the bulb, average scolex ratio of 1 : 3 : 2 : 0.1, and a hermaphroditic sac. Grillotia borealis consistently favoured the most anterior regions of the spiral intestine. Seventy-one per cent of 21 attached worms occupied the most anterior chamber of the spiral valve and 52 per cent were embedded in the anterior surface of the spiral valve whorls. Factors which may limit the distribution of G. borealis within the spiral intestine of its host are discussed. Statistically significant differences occur in the mucosal morphology of B. aleutica and B. parmifera for villus length, diameter, spatial arrangement and number per unit area along the antero-posterior axis of the spiral intestine.
Grillotia epinepheli sp.n. is described on the basis of plerocerci found in the body cavity and peritoneum of the teleost, Epinephelus guaza (L.) (Perciformes: Serranidae) caught off Sardinia, Italy. The species is distinguished from congeners by its tentacular armament, particularly in the basal armature. The metabasal region is armed with rows of 8-9 principal hooks beginning on the internal face; hooks 9 (9’), if present, much smaller than hooks 8 (8’) and similar to minute hooks on the external face. There are three intercalary rows consisting of 3, 2 and 4 hooks each. The external face is armed with a longitudinal band of minute hooks arranged in about 4 files. Basal armature well developed and composed of 7-8 rows of falciform and spiniform hooks.