Remarks. Carijoa riisei is considered a fouling organism. The colonies are densely branching, often having a large, bushy appearance, and are white or pale when preserved. The cylindrical calyces of the primary polyps and daughter polyps have eight longitudinal grooves. Specimens of C. riisei are distinguished easily from other branched SAB clavulariids by the sclerites, which are branching, thorny rods and spindles, as opposed to granular bodies of T. sanguinea, T. fruticulosa and T. nelleae. There is some weak fusion of thorny rods. The polyps bear sparse spiculation in the form of small rods, which are located in the polyp bases and basal regions of the mesenteries.

Atlantic distribution: South Carolina to Brazil, Gulf of Mexico, Caribbean; low tide line to 104 m (NMNH records indicate a specimens collected from 309 m off Havana, Cuba, and from 732 m off the Florida Keys; Deichmann (1936) noted a colony from St. Lucia collected from 508 m). (Deichmann, 1936; Bayer, 1961; NMNH collections; SERTC collection).