Okay so somehow i managed to turn something off, and I'm not sure how to get it back

when you click on a product under the product list (like tshirts), it opens the list on the side into the sub categories, which if cool, but in the main section it just says "tshirts...we offer a wide variety of shirts"....how can i get that main part to display the sub categories in there? like either the names of the sub cetegories, or little pictures of them. It used to, but like i said somehow i managed to turn it off.

Here's my site: http://the69line.com/shop/