Spinoncaea ivlevi (Shmeleva, 1966), female, robust form (northwestern equatorial Pacific) A labrum, anterior, white arrow indicating setules (in square), black arrows indicating three marginal teeth (in circle) B maxillule, inset showing enlarged second element on outer lobe C intercoxal sclerite on P1, black arrows indicating ornamentation with long, fine setule, inset showing enlarged setules D posterior part of genital double-somite and postgenital somites showing undulate hyaline frill. Spinoncaea ivlevi (Shmeleva, 1966), male (northwestern equatorial Pacific) E caudal ramus seta II, inset showing enlarged seta II ornamented with a single long spinule.