Architecting and designing : UML 2.5 : Diagram views : Sequence diagram : Messages on Sequence diagram : Message Kind
  
Message Kind
You may specify the Message Kind on page 3 of the Message tab in a Message’s definition. You can specify the following kind of Messages:
Complete: A Complete Message has a filled-in arrow head.
Found: A found Message is denoted with a small black circle at the starting end of the Message.
Lost: A lost Message is denoted with a small black circle at the arrow end of the Message.
Unknown: Has a Closed arrow head.
A graphic depicting how to specify the Message Kind
See also
Message Sort
Go up to
Messages on Sequence diagram