What do numbers on Coinmarket cap mean? On Coinmarket cap there are volumes listed on http://coinmarketcap.com/currencies/bitcoin/#markets but there are some large numbers at the bottom of the page which dont seem to be included in the daily volume total at the top of the page.

What do these numbers mean?
You're looking at the entries that are in gray and marked with an asterisk?  At the very bottom of the page you can see the meaning of the asterisk: "Volume Excluded - No Trading Fees".

It looks like these entries are for exchanges that don't charge a fee to trade.  Their volume figures could be inflated.  Someone on those exchanges could trade Bitcoin for fiat currency and then trade it right back at no cost, a transaction that has no net effect.  This "volume" doesn't really represent someone who had Bitcoin and wanted fiat or vice versa.  So Coinmarketcap has decided not to include those exchanges in their volume total, since they presumably think it could distort the total.