Cadulus fusiformis: Length, 10.37; antero-posterior diameter at aperture, 1; at widest, 1.14; at apex, 0.37; greatest transverse diameter, 1.17 mm. (Pilsbry and Sharp.)

Cadulus fusiformis: Shell but little curved, long and slender, the greatest diameter contained about 9 times in the length of the Shell ; swelling hardly perceptible, the tube very gradually enlarging from the small apex to the beginning of the last third of the length; thence an equal size is maintained almost to the aperture, just before which it is gently but quite perceptibly contracted on all sides. Surface smooth and glossy, bluish-white, scarcely translucent, with oblique rings of more opaque white, and near the apex some longitudinal white lines; a pellucid ring bordering the lip-edge, behind which there is a short, opaque, white tract, passing gradually into the bluish and banded general colon Tube a mere trifle compressed vertically at the widest part. Aperture oblique, and (measured obliquely) a trifle longer than wide (in the ratio of 35:33) ; lip thin, sharp. Anal orifice circular and simple.

Cadulus fusiformis: Monterey, California, to Cape San Lucas, Lower California.
Fossil : Pliocene, San Diego well.

Cadulus fusiformis: TYPE in United States National Museum, No. 133809. Type locality, San Pedro, California.