jQuery(document).ready(function () {
    jQuery('#mycarousel').jcarousel({
       visible: 4,
        wrap: 'circular',
        scroll: 1,
        itemFirstInCallback: firstInCallbackFunction,
        itemFirstOutCallback: firstOutCallbackFunction,
        itemLastInCallback: lastInCallbackFunction,
        itemLastOutCallback: lastOutCallbackFunction
   });
});

function firstInCallbackFunction(jcarousel_object, li_object, index, state) {
     $(li_object).toggleClass('BoxFirst');

}
function firstOutCallbackFunction(jcarousel_object, li_object, index, state) {
   $(li_object).toggleClass('BoxFirst');
}

function lastInCallbackFunction(jcarousel_object, li_object, index, state) {
    $(li_object).toggleClass('BoxLast');
}

function lastOutCallbackFunction(jcarousel_object, li_object, index, state) {
     $(li_object).toggleClass('BoxLast');
}