671. The determinative pronoun #is#, _that_, _the aforesaid_, _the one_,
is declined as follows:
+--------+-------------------+---------------------------------+
| | Singular. | Plural. |
+--------+-------------------+---------------------------------+
| | MASC. FEM. NEUT. | MASC. FEM. NEUT. |
| _Nom._ | is ea id | eī, iī, eae ea |
| | | or ī |
| _Gen._ | eius eius eius | eōrum eārum eōrum |
| _Dat._ | ē̆ī ē̆ī ē̆ī | eīs, iīs, eīs, iīs, eīs, iīs, |
| | | or īs or īs or īs |
| _Acc._ | eum eam id | eōs eās ea |
| _Abl._ | eō eā eō | eīs, iīs, eīs, iīs, eīs, iīs, |
| | | or īs or īs or īs |
+--------+-------------------+---------------------------------+
672. #is# and #id# (659) are formed from a stem #-i-#, and the other
parts from a stem #eo-#, #eā-#. The genitive is sometimes written in
Cicero and Plautus #eiius#; for the quantity of the first syllable of
#eius#, see 153, 2; for #ĕ̄i#, see 127, 3, and 127, 4.
673. In old verse, the genitive singular rarely has the first syllable
short. Old and rare forms are: D. F. #eae#, Ac. M. #im# or #em#. Pl. D,
and Ab. #ī̆bus#, F. #eābus# (442). In dramatic verse, #e͡um#, #e͡am#,
#e͡i#, #e͡o#, #e͡a#, and #e͡i#, #e͡orum#, #e͡arum#, #e͡os#, #e͡as#,
#e͡is#, are often found; also #eccum#, #eccam#, #eccōs#, #eccās#,
#ecca#, for #ecce eum#, &c.