436. #-ā-# of the stem was shortened in the nominative and accusative
singular at an early period (130, 132). A few apparent examples of the
nominative in #-ā#, found in the oldest writers, seem due to metrical
causes: as, #aquilā́# (Enn.). But #-ā# occurs in Greek proper names
(445). A couple of old masculine nominatives in #-ās# are quoted (422):
#pāricīdās#, _murderer_, and #hosticapās#, _taker of enemies_. In the
accusative singular #-ām# occurs once: #inimīcitiā́m# (Enn.).
437. The genitive sometimes ends (1.) in #-āī# in poetry: as, #aulāī#,
_of the hall_; #pīctāī#, _embroidered_; (2.) in #-ās#: as, #molās#, _of
a mill_. This genitive is rare, but was always kept up in the word
#familiās# with #pater# or #māter#, sometimes with #fīlius# or #fīlia#:
#pater familiās#, _the goodman_, #māter familiās#, _the housewife_. But
#pater familiae#, or in the plural #patrēs familiārum#, is equally
common.
438. Town names and a few appellatives have a locative case in #-ae#:
as, #Rōmae#, _at Rome_, _in Rome_; #mīlitiae#, _in war_, _in the field_,
_in the army_.