.nav{margin:10px;}
.RollDiv {
    margin: 0 auto;
    width: 1000px;
    height: 38px;
    border: 1px solid white;
    overflow: hidden;
}
.RollDiv > div {
    overflow: hidden;
    height: 38px;
    width: 1664px
}
.RollDiv > div > a
{ float:left; display:block;}
.RollDiv > div > a > img {
    width: 138px;
    height: 38px;
    margin-right: 5px;
}