Shell small, solid, with prominent protoconch. Protoconch white, narrow, with 4 convex whorls, presenting an evident suture. About 15 axial ribs, which do not reach the upper suture, appear in the last two whorls.
Teleoconch of about 5 whorls, flat, with the suture similar to the separation between cords, with three spiral cords on each whorl, the upper two closer in all the whorls. There are about 18 axial ribs on the last whorls. They form rounded nodules in the crossing points with the spiral cords. Aperture ovoid, the external lip broken in the holotype. Siphonal canal short and open. Colour of the teleoconch uniformly brown. The specific name refers to the presence of axial ribs on the protoconch.

The typical axial ribs of the protoconch distinguishes the present species from most of the species known in this area.
- Cerithiopsis prieguei Rolan & Espinosa, 1996 has small axial ribs in the protoconch and strong spiral cords. The spiral cords 1-2 are closer to each other.
- Prolixodens ara has axial ribs in all the proto¬conch whorls, but they are crossed by spiral cords and the colour of the teleoconch is different.
- Cerithiopsis aralia Olsson & Harbison, 1953 is a fossil species which was represented in Ode (1989) for a recent shell, but his drawings of the protoconch show that the axial ribs are extended to most of the protoconch, which does not occur in C. apexcostata.

Distribution: The species mentioned from the northwest of the Gulf of Mexico by Ode (1989) is not this species. As a consequence, it is only known from Cuba. Type locality: Cienfuegos, Cuba.