Jhylum Jailum, Or Jelum (anc. Hydaspes; Sanskrit Vitastd; modern Hindoo, Behut), the most western of the five great rivers of the Punjaub, British India. It rises in the N. W. Himalaya, in the southern part of Cashmere, flows N. W. along the centre of the valley of Cashmere in a winding course for about 120 m., more than half being navigable, and after various deviations finds an outlet through the pass of Baramula, and thence proceeds in a western direction toward the vicinity of Mazufarabad. Thence, enlarged by the almost equally considerable Kishen Gunga river, it pursues a S. direction until it falls into the Chenaub, after an entire course of about 450 m. It abounds in fish, and is said to contain alligators. Horace called the river fabulosiis Hydaspes, on account of the wonderful stories associated with it. Virgil refers to it as Medus Hydaspes, and Ptolemy calls it Bidaspes. Alexander is reported to have seen crocodiles on the banks of this river, on which he built his fleet for the war with Porus from the timber of the Himalaya forests.