Radiolaria of the families Haplotaeniatumidae Won, Blodgett, and Nestor, 2002 and Inaniguttidae Nazarov and Ormiston, 1984 were recovered from the Llandovery and lower Wenlock of the Cape Phillips Formation on Cornwallis Island, Nunavut, Canada. Three new species of haplotaeniatumids are described. Haplotaeniatum fissura n. sp. is diagnosed by a densely constructed outer layer around a less dense interior; Haplotaeniatum nunavutensis n. sp. has small, circular pores separated by wide lattice bars; and Orbiculopylorum granti n. sp. possesses robust external spines. Haplotaeniatumids described in open nomenclature are Haplotaeniatum labyrintheum?, Haplotaeniatum aff. cathenatum, Haplotaeniatum cf. raneatela, Haplotaeniatum species A, Orbiculopylorum aff. adobensis, Orbiculopylorum cf. marginatum and Orbiculopylorum species A. Gyrosphaera Noble and Maletz, 2000 is synonymized with Haplotaeniatum. The Inaniguttidae are assigned to Plussatispila n. gen. The genus is diagnosed by two, well-spaced lattice shells and at least seven main spines; additional shells may be present. Plussatispila magnilimax n. sp. has a total of four shells, and P. cornwallisensis n. sp. a total of three. Plussatispila delicata n. sp. has only the two fundamental shells of the genus and is slightly more delicate than the other inaniguttids. Plussatispila pellicia n. sp. possesses weakly developed spines and may have additional irregular layers.