MongoDB nearSphere only returns 100 results?

Why a $nearsphere query always returns 100 results?

 db.mytable.find({"geo":{"$nearSphere":[41.393552,2.171344999999974],"$maxDistance":0.007}}).limit(500).count() -->>> 100 results

No matter about the value of $maxdistance, my table has more than 30.000 records.