Shell very small and convolute. The thickened outer lip encompasses the apex, spire concave where the callous ends. Inside of the outer lip with about 16 crenulations, the base of the columella with 4 folds. 3 specimens were found in between some 60 specimens of C. ovuliformis in the latter species the outline of the spire runs rather smooth. More specimens are known to us from a depth of 50 m near Santa Martha.
Marginella (Granula) agger Watson, 1886, was described as: 2.1 x 1.4 mm, outer lip in the middle blunt but above and below is bevelled outward to a sharp edge. It is thickened externally by a labial varix, which is continued round the outside of the posterior canal which is deep and rounded, and truncates the tip of the shell. Loc. off Culebra island, W.I., 390 fms. G. antillensis differs from agger by its less rounded outlines and by the outer lip not being bevelled outward to a sharp edge. Type locality: Curaçao.