Holotype: Shell of medium to small size for the subgenus; uniformly black, aperture bluish gray within, surface texture waxen; sutures weakly impressed, subsutural area swollen, subsutural cord a prominent keel. Protoconch of 2 smooth, glossy brown whorls; post-nuclear whorls 9. First postnuclear whorl with 9 slanting axial folds, second postnuclear whorl with about 18 nearly vertical ribs crossed by 3 narrow cords; the first 4 post-nuclear whorls impart a concave outline to the spire; axial ribs on final whorl 18, arising below the subsutural cord and curving across the base; spiral sculpture of fine striae, increasing in strength toward the pillar. The suture rises on the last 1/4 turn, the lip massively swollen back of the edge. Sinus U-shaped, shallow and narrow, directed laterally across the thickened lip; stromboid notch slight; anterior canal broad and shallow, twisted to the right, inner lip callus layered. Height, 15.3, diameter, 6.6 mm.

Crassispira coracina has a narrow, laterally directed sinus unlike that of any other species known to us. The other Striospiras have a parietal tubercle and a more upward directed sinus, but C. coracina is tentatively placed here because the sinus is shallow and the suture rises on the last whorl. No radula was found in 2 of the paratype specimens. Mexican specimens average several mm smaller than those from Panama and Costa Rica and have less pronounced axial ribbing. The name coracina means black as a raven, an appropriate designation for these shells.

Pacific Coast of Central America. From Mexico to Colombia. Type Locality: Venado Island, Panama Canal Zone.