51. One, I say, of the rivers which the Scythians have is the Ister; and after it the Tyras, which starts from the North and begins its course from a large lake which is the boundary between the land of the Scythians and that of the Neuroi. At its mouth are settled those Hellenes who are called Tyritai. 52. The third river is the Hypanis, which starts from Scythia and flows from a great lake round which feed white wild horses; and this lake is rightly called “Mother of Hypanis.” From this then the river Hypanis takes its rise and for a distance of five days’ sail it flows shallow and with sweet water still; 591