Port pos center

2

You need headclip and/or tailclip in addition to nodename:portname:compasspoint

digraph top {
    node[shape=none]
    i [label=<<TABLE CELLSPACING="5" CELLPADDING="4" BORDER="0" CELLBORDER="1">
    <TR>
      <TD port="am">top of the morning</TD>
    </TR>  
    <TR>
      <TD port="cow">cattle crossing</TD>
    </TR>  
    <TR>
      <TD>d</TD>
    </TR>  
    </TABLE>> ]
    
  j [label=<<TABLE CELLSPACING="5" CELLPADDING="4" BORDER="0" CELLBORDER="1">
    <TR>
      <TD port="pm">afternoon</TD>
    </TR>  
    <TR>
      <TD>d</TD>
    </TR>  
    </TABLE>> ]

    p -> i:am:c [headclip=false]
    j:pm:c -> i:cow:c [headclip=false tailclip=false]
}

Giving:
htmlFont2