The basis of classification was first fairly recognized by John Ray (1628-1705) and Francis Willughby (1635-72), who, with other and varied scientific labors, undertook, in the "Historia Piscium," published in Oxford in 1686, to bring order out of the confusion left by their predecessors. This work, edited by Ray after Willughby's death, is ostensibly the work of Willughby with additions by Ray. In this work 420 species were recorded, 180 of which were actually examined by the authors, and the arrangement chosen by them pointed the way to a final system of nomenclature. Direct efforts in this direction, with a fairly clear recognition of genera as well as species, were made by Lorenz Theodor Gronow, called Gronovius, a German naturalist of much acumen, and by Jacob Theodor Klein (1685-1757), whose work, "Historic Naturalis Piscium," published about 1745, is of less importance, not being much of an advance over the catalogue of Rondelet. Far greater than any of these investigators, and earlier than either Klein or Gronow, was he who has been justly called the Father of Ichthyology, Petrus (Peter) Artedi (1705-35). Artedi was born in Sweden. He was a fellow student of Linnæus at Upsala, and he devoted his short life wholly to the study of fishes. He went to Holland to examine the collection of East and West Indian fishes of a rich Dutch merchant in Amsterdam named Albert Seba, and there at the age of twenty-nine he was, by accident, drowned in one of the Dutch canals. "His manuscripts were fortunately rescued by an Englishman, Cliffort," and they were edited and published by Linnæus in a series of five parts or volumes. Artedi divided the class of fishes into orders, and these orders again into genera, the genera into species. The name of each species consisted of that of the genus with a descriptive phrase attached. This cumbersome system, called polynomial, used by Artedi, Gronow, Klein, and others, was a great advance on the shifting vernacular, of which it now took the place. But the polynomial method as a system was of short duration. Linnæus soon substituted for it the convenient, in fact inevitable binomial system which has now endured for 150 years, and which with certain modifications must form the permanent substructure of the nomenclature in systematic zoology and botany. The genera of Artedi are in almost all cases natural groups, corresponding essentially equivalent to the families of to-day. Families in ichthyology were first clearly recognized and defined by Cuvier. The following is a list of Artedi's genera and their arrangement: ORDER MALACOPTERYGII.