Owing to the courtesy of Dr G. M. Vevers I have had the opportunity of examining a marine Ichthyobdellid leech, taken by Dr F. A. Phillipps from the cloaca of a shark, 7 feet long, caught between the islands of Aore and Santu, New Hebrides. The leech resembles Pontobdella superficially in being covered by warty tubercles. It possesses, however, certain peculiarities described below which justify its recognition not only as a new species but also as a representative of a new genus.