439. Compounds ending with #-cola#, _inhabiting_, and #-gena#, _born_,
and patronymics, sometimes have the genitive plural in #-ū̆m# in poetry:
as, #caelicolū̆m#, _of occupants of heaven_; #Graiugenū̆m#, _of
Greek-born men_; #Aeneadū̆m#, _of Aeneas’s sons_; also names of peoples:
as, #Lapithū̆m#, _of the Lapithae_. With these last #-ū̆m# occurs even
in prose: as, #Crotōniātū̆m#, _of the Crotona people_. Others in #-ŭm#
are #drachmŭm#, #amphorū̆m#.
440. In the dative and ablative plural, #-eis# sometimes occurs (443):
as, #tueis ingrātieis#, _against your will_ (Plaut.). Nouns in #-ia#
have rarely a single #ī#: as, #pecūnīs#, _by moneys_ (Cic.); #taenīs#,
_with fillets_ (Verg.); #nōnīs Iūnīs#, _on the fifth of June_ (Cic.).
See 24.
441. In the dative and ablative plural, words in #-āia#, or plural
#-āiae#, have #-āīs#, and those in #-ēia# have #-ēīs# (127, 7): as KAL.
MAIS, _on the calends of May_ (inscr.); #Bāīs#, _at Bajae_ (Hor.);
#plēbēīs#, _plebeian_.
442. The dative and ablative plural sometimes end in #-ābus#,
particularly in #deābus#, _goddesses_, and #fīliābus#, _daughters_, to
distinguish them from #deīs#, _gods_, and #fīliīs#, _sons_. #ambae#,
_both_, and #duae#, _two_, regularly have #ambābus# and #duābus#.