a. The Ablative Singular commonly ends in -í, but sometimes -e.
1. Adjectives used as nouns (as superstes, survivor) have -e.
2. Participles in -ns used as such (especially in the ablative absolute, § 419), or as nouns, regularly have -e; but participles used as adjectives have regularly -í: -
3. The following have regularly -í: - áméns, anceps, concors (and other compounds of cor), cónsors (but as a substantive, -e), dégener, hebes, ingéns, inops, memor (and compounds), pár (in prose), perpes, praeceps, praepes, teres.
4. The following have regularly -e: - caeles, compos, [déses], díves, hospes, particeps, pauper, prínceps, sóspes, superstes. So also patrials (see § 71. 5) and stems in át-, ít-, nt-, rt-, when used as nouns, and sometimes when used an adjectives.
b. The Genitive Plural ends commonly in -ium, but has -um in the following:[1][Forms in -um sometimes occur in a few others.] -
1. Always in compos, díves, inops, particeps, praepes, prínceps, supplex, and compounds of nouns which have -um: as, quadru-pés, bi-color.
2. Sometimes, in poetry, in participles in -ns: as, silentum concilium, a council of the silent shades (Aen. vi. 432).
c. The Accusative Plural regularly ends in -ís, but comparatives commonly have -és.
d. Vetus (gen. -eris) and púbes (gen. -eris) regularly have -e in the ablative singular, -a in the nominative and accusative plural, and -um in the genitive plural. For úber, see § 119.
e. A few adjectives of one termination, used as nouns, have a feminine form in -a: as, clienta, hospita, with the appellative Iúnó Sóspita.