Seeking Grammar Police Ruling - Typo's / that possessive 's

[potioncat]

> Mike: 
> And I always wondered what one does with a surname that ends in s. 
> That is, if there is a James Dents and all the little Dents. How 
> would one distinguish between one of the Dents owning something as 
> opposed to the entire family owning it? If I were to say "Dents' 
> automobile" am I referring to it as James' car or the Dents' family 
> car? 
> 
> I supposed I could just call it the "Dense car", though James may not 
> appreciate that. ;D


Potioncat:
I thought all plural words ending in s just add an '. Proper nouns that 
end in s have an 's to show possessive. So it would be James's car. As 
to the Dents family. This is Mr. Dents's car. That is the Dentses' van.
Or am I missing something in your post?

Of course, if you were saying Dents's or Dentses' it would sound alike 
So you might have to say, this car belongs to the Dents family, that 
car belongs to Mr. Dents.