HIRUDO. See Encycl. A new species of this insect was discovered in the South Sea by Le Martiniere, naturalist in Perouse's voyage of discovery. He found
it buried about half an inch in a shark's liver, but could not conceive how it had got thither. It was something more than an inch long, of a whitish colour, and composed of several rings similar to those of the trænæ. The superior part of its head was furnished with four small ciliated mammillæ, by which it took its food; under each manilla on both sides was a small oblong pouch, in the form of a cup; and in the form of its instrumenta cibaria, it very nearly resembles the animal which has been supposed to be the cause of measles in swine. Both these species are referable to the genus hirundo, the characters of which, as given by Linnæus, stand (says Martiniere) in need of reformation.