[*] 79.
In many nouns the stem is irregularly modified in the nominative or other
cases. Some peculiar forms are thus declined:—
[*] a.
Two vowel-stems in
ū-,
grū- and
sū-, which follow the third declension, add
s in the nominative, and are inflected like mute stems:
grūs has also a nominative
gruis; sūs has
both
suibus
and
sū˘bus in the dative and
ablative plural,
grūs has only
gruibus
.
[*] b.
In the stem
bov- (
bou-) the diphthong
ou becomes
ō in the nominative (
bōs,
bŏvis).
In
nāv- (
nau-) an
i is added (
nāvis
,
-is), and it is declined like
turris
(§ 67).
In
Iŏv- (=
Ζεύς) the diphthong (
ou
) becomes
ū in
Iū-piter (for
-păter), genitive
Iŏvis
, etc.; but the form
Iuppiter
is preferred.
[*] c.
In
iter
,
itineris
(N.),
iecur,
iecinoris (
iecoris
) (N.),
supellēx
,
supellēctilis (F.), the nominative
has been formed from a shorter stem; in
senex
,
senis
, from a longer; so that these words show a combination of
forms from two distinct stems.
[*] d.
In
nix,
nivis
the nominative retains a
g from the original
stem, the
g uniting with
s, the nominative
ending, to form
x. In the other cases the stem assumes the
form
niv- and it adds
i in the
genitive plural.
[*] e.
Vās
(N.),
vāsis
, keeps
s throughout; plural
vāsa
,
vāsōrum
. A dative plural
vāsibus also occurs.
There is a rare singular
vāsum
.
