How can I remove these links from page?

I'm trying to remove the links towards the bottom of certain post that link to the next page and previous post. This page is an example:http://tinyurl.com/lk3w8sk

I've tried the code below, but it's still not targeting the area.

body.single.single-portfolio.postid-6777 #single-nav {display: none;}

.postid-6777 #single-nav {display: none}