Herbert Weir Smyth, A Greek Grammar for Colleges

a. So ὁ λεώς people, ὁ Μενέλεως Menelaus, ὁ λαγώς hare. Observe that ω is found in every form, and that it takes ι subscript in the dative of all numbers where an ordinary ο stem has ι.

b. There are no neuter substantives belonging to the Attic declension in standard classical literature; but neuter adjectives (289) end in -ων.

c. νεώς and most words of this declension owe their forms to transfer of quantity (34) or to shortening (39). Thus, νεώς is from νηός ( = Doric να_ός), νεών from νηόν; νεῴ is from νηῷ. λαγώς is contracted from λαγωός.

d. In the accusative singular some words end in -ω or -ων, as λαγώ or λαγών hare. So ὁ Ἄθως, ἡ Κέως, ἡ Τέως, ἡ Κῶς, ὁ Μί_νως. ἡ ἕως dawn always has ἕω.