THE OKEANIDES or NYMPHAI ARTEMISIAI were a band of sixty young Okeanid Nymphs which formed the core retinue of the goddess Artemis. Their names suggest they were regarded as Nephelai (Okeanides as cloud nymphs).

Other nymph attendant Nymphai of Artemis included the Naiades Amnisiades, and Nymphai Hyperboreiai.

Aeschylus, Toxotides (lost play) (Greek tragedy C5th B.C.) :
Aeschylus' Toxotides told the story of Aktaion who was turned into a stag and torn apart by his own dogs. According to Weir Smyth (L.C.L.) "The common version of the legend--that he was punished by Artemis for having seen her bathing--seems to have been adopted by Aeschylus. The Chorus of Archer-Maidens (Toxotides) were nymphs, attendants of Artemis in the chase."

"[Artemis to Zeus] ‘And give me sixty daughters of Okeanos (Okeanines) for my choir - all nine years old, all maidens yet ungirdled; and give me for handmaidens twenty Nymphai of Amnisos (Amnisides) who shall tend well my buskins, and, when I shoot no more at lynx or stag, shall tend my swift hounds." - Callimachus, Hymn III to Artemis 12

"And the maiden [Artemis] fared unto the white moutain of Krete leafy with woods; thence unto Okeanos; and she chose many Nymphai all nine years old, all maidens yet ungirdled. And the River Kairatos was glad exceedingly, and glad was Tethys that they were sending their daughters to be handmaidens to the daughter of Leto.
And straightway she [Artemis] went to visit the Kyklopes … And the Nymphai [companions of Artemis] were affrighted when they saw the terrible monsters like unto the crags of Ossa … The Okeaninai could not untroubled look upon them to face nor endure the din in their ears. No shame to them!" - Callimachus, Hymn III to Artemis 40

"Like Artemis, standing in her golden chariot after she has bathed in the gently water of Parthenios or the streams of Amnisos, and driving off with her fast-trotting deer over the hills and far away to some rich-scented sacrifice. Attendant Nymphai have gathered at the source of Amnisos or flocked in from the glens and upland springs to follow her; and fawning beasts whimper in homage and tremble as she passes by." - Apollonius Rhodius, Argonautica 3.879

"Dictynna [Artemis] across high Maenalus [in Arkadia] progressing with her troop, proud of her kills, observed the girl [Kallisto] and called her ... She saw the Nymphae came with their queen ... and joined their company .... [and Kallisto] stayed by her goddess’ side and led the train." - Ovid, Metamorphoses 2.441

"There was a valley clothed in hanging woods of pine and cypress, named Gargaphie, sacred to chaste Diana [Artemis], huntress queen. Deep in its farthest combe, framed by the woods, a cave lay hid, not fashioned by man’s art, but nature’s talent copied artistry, for in the living limestone she had carved a natural arch; and there a limpid spring flowed lightly babbling into a wide pool. Its waters girdled with a grassy sward. Here, tired after the hunt, the goddess loved her Nymphae to bathe her with the water’s balm. Reaching the cave, she gave her spear and quiver and bow unstrung to an attendant Nympha; others received her robes over their arms; two loosed her sandals; more expert than these Crocale tied the hair loose on her shoulders into a knot, her own hair falling free. Then Nephele and Hyale and Rhanis and Phiale and Psecas brought the water in brimming jars and poured it over her. And white Titania [Artemis] bathed there in the pool, her loved familiar pool, it chanced the grandson of Cadmus [Aktaion], the day’s hunt finished, idly wandering through unknown clearings of the forest, found the sacred grove - so fate guided him - and came upon the cool damp cave. At once, seeing a man, all naked as they were, the Nymphae, beating their breasts, filled the whole grove with sudden screams and clustered round Diana [Artemis] to clothe her body with their own. But she stood taller, a head taller than them all; and as the clouds are coloured when the sun glows late and low or like the crimson dawn, so deeply blushed Diana [Artemis], caught unclothed. Her troop pressed close about her, but she turned aside and looking backwards (would she had her arrows ready!) all she had, the water, she seized and flung it in the young man’s face [transforming him into a stag]." - Ovid, Metamorphoses 3.155

"[Dionysos to Nikaia:] ‘I will fetch you myself sixty dancing handmaids, to complete the unnumbered dance that attends you, as many as the servants of the mountain Archeress [Artemis], as many as the daughters of Okeanos; then Artemis hunting will not rival you, even if she be the mistress of the hunt." - Nonnus, Dionysiaca 16.127

"[Artemis] and maiden Aura mounted the car [Artemis' chariot], took reins and whip and drove the horned team like a tempest. The unveiled daughters of everflowing Okeanos her servants made haste to accompany the Archeress: one moved her swift knees as her queen’s forerunner, another tucked up her tunic and ran level not far off, a third laid a hand on the basket of the swiftmoving car and ran alongside. Archeress diffusing radiance from her face stood shining above her attendants ... The goddess [Artemis] leapt out of her car [of her chariot]; Oupis took the bow from her shoulders, and Hekaerge the quiver; the daughters of Okeanos took off the well-strung hunting nets, and another took charge of the dogs; Loxo loosed the boots from her feet." - Nonnus, Dionysiaca 48.302

Sources:

• Aeschylus, Fragments - Greek Tragedy C5th B.C.
• Apollonius Rhodius, The Argonautica - Greek Epic C3rd BC
• Callimachus, Hymns - Greek C3rd BC
• Ovid, Metamorphoses - Latin Epic C1st BC - C1st AD
• Nonnos, Dionysiaca - Greek Epic C5th AD