Four remarkable dome-shaped, apparently juvenile colonies, belonging to the genus Pyrostremma Garstang, 1929, are described from the Bermuda area. Comparison with juvenile colonies of P.agassizi (Ritter & Byxbee, 1905), and with larger colonies, fragments and loose zooids of P.agassizi and P.spinosum (Herdman, 1888), has rendered it likely, that these juvenile colonies belong to P.spinosum. The species of Pyrostremma are discussed.