The anterior (head) end is narrow and is armed with a sucker with which the leech holds onto the turtle host.

This end also bears a mouth on the underside near the sucker and a pair of eyes on the fifth annulation.

[2] Ozobranchus branchiatus is found on the eastern coast of North America, its range extending from Cape Hatteras in North Carolina, southwards round the coast of Florida to the western Caribbean Sea and the Gulf of Mexico.

A green sea turtle in the Persian Gulf was found to have about 1400 leeches of this species, about 300 in each of the axillary and inguinal areas beneath the limbs, and about 200 on the throat, in front of the intergular scute.

[2] This leech has been implicated as a vector of the fibropapilloma virus (FPTHV), a herpesvirus that causes lethal tumour growths on various parts of the turtle's body.