Right now I can only think of one instance in which this regularly occurs. The adjective *proper* is sometimes placed after the noun it modifies, e.g:

> 
> [**Reptilia:**](http://www.wordnik.com/words/reptilia) A class of cold-blooded oviparous or ovoviviparous vertebrated animals whose skin is covered with scales or scutes; **the reptiles proper**.
> 
> 
> 

What is this word order called, and why is it ever used?

Edit: I really want to know about *proper*, and while the word *hyperbaton* relates to post-positivity when it is meant to be rhetorically impacting, it doesn't seem to fit with ubiquitous post-positivity, such as that of *proper*. I've accepted *hyperbaton* as the correct term/reason for almost all post-positive constructions, but I'd like a complete answer to include *proper*.