3. Participles in -āns and -ēns follow the declension of ī-stems. But they
do not have -Ä« the Ablative, except when employed as adjectives; when used
as participles or as substantives, they have -e; as,--

ā sapientī virō, _by a wise man_; but
ā sapiente, _by a philosopher._
Tarquiniō rēgnante, _under the reign of Tarquin._

4. Plūs, in the Singular, is always a noun.

5. In the Ablative Singular, adjectives, when used as substantives,--

a) usually retain the adjective declension; as,--

aequālis, _contemporary_, Abl. aequālī.
cōnsulāris, _ex-consul_, Abl. cōnsulārī

So names of Months; as, Aprīlī, _April_; Decembrī, _December_.

b) But adjectives used as proper names have -e in the Ablative Singular;
as, Celere, Celer; Juvenāle, _Juvenal_.

c) Patrials in -ās, -ātis and -īs, -ītis, when designating places
regularly have -ī; as, in Arpīnātī, _on the estate at Arpinum_, yet -e,
when used of persons; as, ab Arpīnāte, _by an Arpinatian_.

6. A very few indeclinable adjectives occur, the chief of which are frūgī,
_frugal_; nēquam, _worthless_.

7. In poetry, adjectives and participles in -ns sometimes form the Gen.