[jQuery] Removing element from DOM after animate

Please tell me why the remove() doesn't work from this call:
$(this).parents(".leftbox:first").animate({height:"hide",
opacity:"hide"}, 350, "", function(){$(this).remove()});


while this one works:
$(this).parents(".leftbox:first").animate({height:"hide",
opacity:"hide"}, 350).remove();


Thanks in advance.