1997 Jeep Wrangler Exhaust Manifold

I have a "Y" pipe just under my exhaust manifolds that is cracked. In my haynes repair manual it does not say anything about it that I can find. It is not part of the exhaust manifold. I am not sure what it is called. Can you help me out?
[img:8355ddf584]http://www.2carpros.com/forum/automotive_pictures/459020_1203091016_1.jpg[/img:8355ddf584]

[img:8355ddf584]http://www.2carpros.com/forum/automotive_pictures/459020_1203091016a_1.jpg[/img:8355ddf584]