In article , jane jane@moonros
e.demonmapson.co.uk writes

Surely if the ending in singular is -is then the plural is -um?

as in
singular:
arbor
arborem
arboris
arbori
arbore

plural:
arbores
arbores
arborum
arboribus
arboribus

:-)


Wrong example! You need something where the nominative ends in 'is' not
the genitive ;-)

eg civis pl cives .... which doesn't help your case ;-)
--
Kay
"Do not insult the crocodile until you have crossed the river"