Default port is 27017. You might have to forward it:
ssh -L 27018:127.0.0.1:27017 [email protected]
To clone the a database:
mongo
> db.copyDatabase("mongoid", "mongoid", "127.0.0.1:27018");
{ "ok" : 1 }
To get some info about a certain DB:
mongo localhost/mongoid
> db.stats();
{
"db" : "mongoid",
"collections" : 16,
"objects" : 21452,
"avgObjSize" : 768.0516501957859,
"dataSize" : 16476244,
"storageSize" : 25385984,
"numExtents" : 43,
"indexes" : 70,
"indexSize" : 15450112,
"fileSize" : 469762048,
"ok" : 1
}