Jacforus is a small crab, with a carapace around 5 millimetres (0.20 in) long and 7 mm (0.28 in) wide.

[1] Jacforus cavatus has a wide distribution in the tropical Indo-Pacific, ranging from Kenya to Australia, Japan and Hawaii.

[1] It was described again by Charles Howard Edmondson in 1925 as Euxanthus minutus, and again by Edmondson in 1931 as Megametope sulcatus, both of which are junior subjective (heterotypic) synonyms.

[1] The affinites of Rathbun's species with other genera have also been unclear;[1] its apparent affinities with the genus Medaeus are superficial.

[1] A new genus, Jacforus, was erected in 2003, commemorating Jacques Forest,[1] and containing only J. cavatus.