Gallery slideshow

I have read that you can insert a gallery slideshow without a plugin but mine doesn’t have the slideshow feature. I am using the latest version of WordPress (3.8.1) and can insert a gallery, but there are no options to create a slideshow. How do I activate the newer features described on http://en.support.wordpress.com/slideshows/ ?

My site is http://whchurchofchrist.org/test/wordpress

Thanks.