LAGENORHYNCHUS (la-je-nō-ring'kus), a genus of Delphinidæ. The beak of the upper jaw keeled on each side, the lower jaw with two or three small, conical, rudimentary teeth in the middle of each side. L. leucopleurus, the Delphinus tursio of Knox, occurs in Orkney and the Northern Ocean generally. L. albirostris is the white-beaked bottlenose. It has been taken on the coast of Norfolk, England.