Peter, an eminent naturalist, was born in Sweden in the year 1705, in the province of Angermania. Although his parents were poor, yet it appears they found means to give him a liberal education, and with this view they sent him to the college of Hurnefeld. Intending to embrace the ecclesiastical profession, he went in 1724 to Upsal; but being fond of the study of natural history, he yielded to the bent of inclination, and directed his attention towards medicine. In natural history he made rapid progress, and soon rose to considerable eminence, particularly in the knowledge of Ichthyology. His reputation for natural knowledge was high when Linnaeus arrived at Upsal in the year 1728. A lasting friendship was formed between these two great men. Confining his botanical studies to the umbelliferous plants, he suggested a new mode of classification; but Arvedi was much better acquainted with chemistry than botany. His attention was chiefly directed to ichthyology, the classification of which he greatly reformed, and new-modelled upon philosophical principles. This arrangement added greatly to his reputation as a naturalist. When the two friends were about to leave Upsal, Linnaeus to go to Lapland, and Arvedi to England, they reciprocally bequeathed to each other their manuscripts and books upon the event of death. In the year 1735, they, however, met again at Leyden, where Arvedi was introduced to Seba, and employed in preparing for the press the third volume of that eminent naturalist's Theatrum, which chiefly related to fishes. Arvedi formed the resolution, as soon as that work was finished, to return to his native country, to publish the fruits of his own labours; but unfortunately as he was returning home from Seba's house on the evening of September 27, 1735, the night being dark, he fell into the canal and was drowned. According to agreement, his manuscripts came into the hands of Linnaeus, and he published his Bibliotheca Ichthyologica, and Philosophia Ichthyologica, together with a life of the author, at Leyden in the year 1738. (Gen. Biog.)