[3] Members of the genus Urceolus are distinguished by the presence of a 'neck' at the anterior end of their oval-shaped cell, followed by a wide aperture or 'mouth' into a deep canal where the feeding groove and the flagellum originate.

In addition, it has a cylindrical neck with margins abruptly truncated, not turned outward as in other species such as U.

[4] The author of the species, Konstantin Mereschkowsky, measured the cell size as 0.039’’’ in length, and 0.024’’’ at the greatest width, without using any symbol of the metric system.

[1] The species Urceolus alenizini was described by Russian biologist Konstantin Mereschkowsky, in a memoir on the protozoa found in northern Russia published in 1877,[2] later translated into German in 1879.

[1] It was described from a rare flagellate seen only once by Mereschkowsky in the White Sea, near the Solovetsky Monastery, distinguished by the unique neck-shaped anterior end of the cell.