Our source for this set of verses, I.14.245–246–246a, is Plutarch On the face in the moon 938d, whose narrative provides a context for including verse 246a in such a set. Without the testimony of Plutarch, we would not know about this verse, since it does not survive in the medieval manuscript tradition. But it had survived, as we know from Plutarch, in the text of the Homeric Iliad as edited by Crates of Mallos, Director of the Library of Pergamon (see under Crates in the inventory of Words and Ideas). In that text, verse 246 of Iliad 14 was followed by another verse, labeled as 246a in modern editions:
I.14.246 Ὠκεανός, ὅσπερ γένεσις πάντεσσι τέτυκται
I.14.246a ἀνδράσιν ἠδὲ θεοῖς, πλείστην <τ᾿> ἐπὶ γαῖαν ἵησιν
Taken together, these verses can be translated this way:
I.14.246 … Ōkeanos, who has been fashioned as genesis for all
I.14.246a men and gods, and he flows over the Earth in all her fullness.
What is said about Ōkeanos in the “plus-verse” I.14.246a as attested here by Crates is closely related to what we find in poetic traditions attributed to Orpheus. The existence of such Orphic traditions is clearly attested in relevant quotations and paraphrases made by Plato, especially in Cratylus 402a-c regarding the role of Ōkeanos as a primordial source of creation. Details in HPC 2§§128–147. As for Crates (F 20 ed. Broggiato 2001), he cited the “plus verse” I.14.246a as evidence in arguing for his theory that the Ōkeanos was a salt-water Ocean covering a spherical Earth. For Crates, then, these verses at I.14.245–246–246a about the Ōkeanos were an essential part of an allegory about the cosmos. According to this theory of Crates, the earth was a sphere, located at the center of a universe that was likewise spherical. Crates evidently interpreted in a modernizing sense the expression at I.14.246a: ‘[which flows] over most of the earth’ (πλείστην … ἐπὶ γαῖαν). In other words, the salt-water ocean covers most of the spherical Earth. This theory was opposed by Aristarchus, Director of the Library of Alexandria (see under Aristarchus in the inventory of Words and Ideas), who viewed the Homeric Ōkeanos as a fresh-water river surrounding an Earth that is circular and flat (HC 2§150). See further my comment at HC 2§153 about this dispute between Crates and Aristarchus. What was at stake, as I say in my comment there, was no trivial matter. In this case, in fact, the stakes were of cosmic proportions. Both sides of the dispute were attempting to establish their theories of the cosmos by way of deciding the rightness or wrongness of different variants in the text of Homer. I find it ironic, I went on to say, that I am describing this ancient state of affairs in an era when it appears fashionable to dismiss Homeric textual variations as “trivial,” “banal,” and even “boring.” There will be more to say in my comment on I.18.478–609, in the context of the Shield of Achilles in Iliad 18, about the conceptualization of Ōkeanos as some primordial work of art as suggested by the verb tetuktai (τέτυκται) ‘has been fashioned’ here at I.14:244. For more on the narrative that is taking shape at I.14.245–246–246a, see the comment on I.14.301–302.