K. serga has a larger and differently sculptured larval shell, a much sharper and more rasp-like sculpture with a few spirals larger than the rest of the Caribbic forms; the angulation more peripheral and less marked, the last whorl longer and narrower proportionally, the notch wide but not quite sutural; the suture distinct, not appressed, marginated by a thread; ribs thirteen, no varix; canal longer; ribs narrow, not strong except on the periphery and almost spinose at the intersection of the primary spirals. Lon. of shell, 9.0 mm; last whorl, 5.12 mm; lat. 3.1 mm.

General distribution. The upper bathyal zone of northern Mid-Atlantic, including the Mediterranean.
Remarks. Many other species have a sculpture of spiral rows of granules but they do not have the long, slender aperture and angular whorls of the present species. The two Kurtziella serga and Mangelia nuperrima can easily be separated from other genera by the larval shell, which resembles that of Benthomangelia, but has fewer whorls and coarser axial sculpture. M. serga has no operculum. The protoconch indicates planktotrophic larval development.

Caribbic. Antilles and Straits of Florida.