49. a. The Locative form of this declension ends fro the singular in -í: as, humí, on the ground; Corinthí, at Corinth; for the plural, in -ís: as, Phillipís, at Phillipi (cf. § 80, footnote).
b. The genitive of nouns in -ius or -ium ended, until the Augustan Age, in a single -í: as, fílí, of a son; Pompêí, of Pompey (Pompêius); but the accent of the nominative is retained: as, inge'ní, of genius.[1][The genitive in -ií occurs once in Vergil, and constantly in Ovid, but was probably unknown to Cicero.]
c. Proper names in -ius have -í in the vocative, retaining the accent of the nominative: as, Vergi'lí. So also, fílius, son; genius, divine guardian: as, audí, mí fílí, hear, my son.
Adjectives in -ius form the vocative in -ie, and some of these are occasionally used as nouns: as, Lacedemonie, O Spartan.
NOTE: Greek names in -íus have the vocative in -íe: as, Lyrcíus, vocative Lyrcíe.
d. The genitive plural often has -um or (after v) -om (cf. § 6. a) instead of -órum, especially in the poets: as, deum, superum, dívom, of the gods; virum, of men. Also in compounds of vit, and in many words of money, measure, and weight: as, Sévirum, of the Seviri; nummum, of coins; iúgerum, of acres.
e. The original ending of the ablative singular (-ód) is sometimes found in early Latin: as, Gnaivód (later, Gnaeó), Cneius.
f. Proper names in -âius, -êius, -ôius (as, Aurunculêius, Bôí, are declined like Pompêius.
g. Deus (M.), god, is this declined: -
| o to 59ptSINGULAR | to 1in PLURAL |
| o to 59pt NOM. deus | to 1in deí (dií), dí |
| o to 59ptGEN. deí | to 1in deórum, deum |
| o to 59ptDAT. deó | to 1in deís, (diís) dís |
| o to 59ptACC. deum | to 1in deós |
| o to 59ptABL. deó | to 1in deís, (diís) dís |
NOTE: The vocative singular of deus does not occur in classic Latin, but is said to have been dee; deus (like the nominative) occurs in the Vulgate. For the genitive plural, dívum or dívom (from dívus, divine) is often used.
Also, the adjective líber, free, of which líberí, children, is the plural (§ 111. a), and compounds in -fer and -ger (stem fero-, gero-): as, lúcifer, morning-star; armiger, squire.
a. An old nominative socerus occurs. So vocative puere, boy, as if from ¥puerus (regularly puer).
b. Vir, man, has genitive virí; the adjective satur, sated, has saturí; vesper, evening, has ablative vespere (locative vesperí, in the evening).
c. Mulciber, Venus, has -berí and -brí in the genitive. The barbaric names Hibér and Celtibér retain é throughout.