Zemacies excelsa is a species of sea snail, a marine gastropod mollusk in the family Borsoniidae.

[1] The shell grows to a length of 55 mm.

Individuals can grow to 58.2mm and can have a wet body mass of 24.5g.

[2] Dead Zemacies excelsa form shallow marine sediments.

This species occurs in the Pacific Ocean off New Caledonia and New Zealand.