Epitonium (Hyaloscala) sykesii (Melvill & Standen, 1903) (Fig. 204) E. sykesii is a deep water species which was described from the Gulf of Oman. It reaches a maximum size of about 9mm. It is white, with about 30 thin blade-like costae per whorl. The costae are not peaked. There are about 5 convex teleo- conch whorls. The aperture is oval and there are at least 2 protoconch whorls. While this species resembles E. amathusium, it differs in having more costae per whorl.

4mm. Superficially resembles E. rissoinaeforme (see above) but outer lip is not greatly thickened and ribs are closer, more sinuous and twice as many (about 45 on last whorl). As each species is known only from the unique haul at 156 fathoms off Muscat, these differences, though apparently significant, may be merely sexual in character. Habitat: deep water. Distribution: Gulf of Oman.