The message
from "BAC" contains these words:

Whilst at school, we were taught that it was incorrect to put an 's' after
the 'possessive' apostrophe in the case of plural words ending in 's'. Hence
we would put, for example, the squirrels' nuts (meaning the nuts put out for
the squirrels); not the squirrels's nuts; certainly not the squirrel's nuts,
which latter would mean we were asserting the squirrel (singular) was nuts.
As an expert in these matters, can you please advise whether that usage is
still regarded as correct?

As a onetime teacher I'll stick my neck out:

"Squirrel's nuts" is perfectly correct for "the nuts of the squirrel";
"Squirrels' nuts" for "the nuts of the squirrels" is perfectly correct;
"Squirrels's nuts" for "the nuts of the squirrels" is also correct,
though not so often used;

"The squirrel's were on the lawn" is wrong, and always has been, even in
the time when an apostrophe was used to adorn the plural of bananas,
avocados, amd many other (usually foreign) words ending in a vowel.

HTH

--
Rusty
horrid dot squeak snailything zetnet point co full-stop uk
http://www.users.zetnet.co.uk/hi-fi/