§49. Case-Forms in the Second Declension

a. The Locative form of this declension ends for the singular in -ī: as, humī, on the ground; Corinthī, at Corinth; for the plural, in -īs: as, Philippīs, at Philippi (cf. p. 34, footnote).

b. The genitive of nouns in -ius or -ium ended, until the Augustan Age, in a single -ī: as, fīlī, of a son; Pompêī, of Pompey ( Pompêius); but the accent of the nominative is retained: as, ingĕ'nī, of genius. ¹

c. Proper names in -ius have -ī in the vocative, retaining the accent of the nominative: as, Vergĭ'lī. So also, fīlius, son; genius, divine guardian: as, audī, mī fīlī, hear, my son.

Adjectives in -ĭus form the vocative in -ie, and some of these are occasionally used as nouns: as, Lacedaemonie, O Spartan.

d. The genitive plural often has -um or (after v) -om (cf. § 6. a) instead of -ōrum, especially in the poets: as, deum, superum, dīvom, of the gods; virum, of men. Also in compounds of vir, and in many words of money, measure, and weight: as, Sēvirum, of the Seviri; nummum, of coins; iūgerum, of acres.

e. The original ending of the ablative singular (-ōd) is sometimes found in early Latin: as, Gnaivōd (later, Gnaeō), Cneius.

f. Proper names in -âius, -êius, -ôius (as, Aurunculêius, Bôī), are declined like Pompêius.

g. Deus (M.), god, is thus declined:—