wordpress css menu help

I'm working on customizing the menu on a wordpress theme. I need css span to be applied inside the link. This works fine for normal links but for links from wp_list_pages it messes up the css.

<li><?php wp_list_pages('title_li='); ?></li>
<li><a href="#"><span>Title</span></a></li>
</ul>

The CSS shows up fine with the link "Title" but shows up incorrect for wp_list_pages.

Is there any way around this? Can I somehow edit the html around wp_list_pages to include span?

More info:

I'm using this css:

<style type="text/css">
<!–
#dolphincontainer{position:relative;height:56px;color:#E0E0E0;background:#143D55;width:100%;font-family:Helvetica,Arial,Verdana,sans-serif;}
#dolphinnav{position:relative;height:33px;font-size:12px;text-transform:uppercase;font-weight:bold;background:#fff url(/code/dolphin/images/dolphin_bg.gif) repeat-x bottom left;padding:0 0 0 20px;}
#dolphinnav ul{margin:0;padding:0;list-style-type:none;width:auto;float:left;}
#dolphinnav ul li{display:block;float:left;margin:0 1px;}
#dolphinnav ul li a{display:block;float:left;color:#EAF3F8;text-decoration:none;padding:0 0 0 20px;height:33px;}
#dolphinnav ul li a span{padding:12px 20px 0 0;height:21px;float:left;}
#dolphinnav ul li a:hover{color:#fff;background:transparent url(/code/dolphin/images/dolphin_bg-OVER.gif) repeat-x bottom left;}
#dolphinnav ul li a:hover span{display:block;width:auto;cursor:pointer;}
#dolphinnav ul li a.current,#dolphinnav ul li a.current:hover{color:#fff;background:#1D6893 url(/code/dolphin/images/dolphin_left-ON.gif) no-repeat top left;line-height:275%;}
#dolphinnav ul li a.current span{display:block;padding:0 20px 0 0;width:auto;background:#1D6893 url(/code/dolphin/images/dolphin_right-ON.gif) no-repeat top right;height:33px;}
–>
</style>

Code (markup):

and this is the navbar file:

<?php global $op_search; ?>

<div id="dolphincontainer">
<div id="dolphinnav">

	<ul id="nav" <?php if($op_search == __('True','options')) echo 'class="nav-search"'; ?>>

		<li<?php if(is_home()) { echo " class=\"current\""; } ?>><span><a href="<?php bloginfo('url'); ?>" title="<?php _e('Home','options'); ?>"><span><?php _e('Home','options'); ?></span></a></li>
		<li><?php wp_list_pages('title_li='); ?></li>
<li><a href="#"><span>Title</span></a></li>
	</ul>

	<?php if($op_search == __('True','options')) include(TEMPLATEPATH . '/includes/searchform.php'); ?>

</div>
</div>

Code (markup):

I have it set up so subpages become dropdown menus, so that might have something to do with it.

All help appreciated! Thanks!