Stellatoma mellissi is a species of sea snail, a marine gastropod mollusk in the family Mangeliidae.
The adult shell grows to a length of 5 mm, its diameter 2 mm. The small shell is fusiform-ovate. It has a reddish color and a darker reddish color at the sutures. The body whorl has a red band in the middle. The shell contains 6ý whorls. The 2ý protoconch whorls are convex and smooth. The third whorl is convex and is slightly obliquely lirate. The others have a broad sloping shoulder and a greatly rounded anterior portion. They show about 14 axial ribs. The spiral sculpture consists of 3 cords in the upperwhorls and 16-20 in the body whorl. The aperture is elongate-ovate, measuring about half the total length. The outer lip is marked by transverse striations and is incrassate with a strong denticle close to the posterior sinus. The microscopic structure of this species appears under the microscope to consist of numerous spiral series of very minute grain-like scales, which, at times, are arranged one under the other, so as to produce the appearance of a longitudinal series.
This species is found in the Atlantic Ocean off St. Helena.