It looks like the Ripple volume is only based on XRP traded against BTC.Bitstamp. There are several other pairs with comparable volume, so XRP seems to be underreported by coinmarketcap (BTC.Bitstamp often has less volume than USD.Bitstamp and CNY.RippleCN).

https://ripplecharts.com/markets shows most of the markets. Several more markets, like XRP/NXT, have developed since ripplecharts.com stopped being updated while v2 of the site is being developed, but the biggest markets are on there.

BTW: Thanks for adding XRP back to the main page!